We perform a numerical simulation of the effects of an orthogonal magnetic field on charge transport and shot noise in an armchair graphene ribbon with a lattice of antidots. This study relies on our envelope-function based code, in which the presence of antidots is simulated through a nonzero mass term and the magnetic field is introduced with a proper choice of gauge for the vector potential. We observe that by increasing the magnetic field, the energy gap present with no magnetic field progressively disappears, together with features related to commensurability and quantum effects. In particular, we focus on the behavior for high values of the magnetic field: we notice that when it is sufficiently large, the effect of the antidots vanishes and shot noise disappears, as a consequence of the formation of edge states crawling along the boundaries of the structure without experiencing any interaction with the antidots. Graphene, a planar hexagonal lattice of carbon atoms, represents one of the currently most studied and promising materials ,2,3,4,5.Since its envelope-function transport equation is formally equivalent to the relativistic Dirac equation ,12,13,14Due, in particular, to its very high mobility and its current carrying capability, graphene has been often considered as a candidate to replace commonly used semiconductors, such as silicon, in “Beyond Moore” nanoelectronics ,30,31,32It has been shown that a gap can be opened in graphene by means of lateral confinement, i.e., by defining a nanoribbon ,33,34; hOther methods have been proposed for opening up an energy gap in graphene ,37, and,B on the transport and noise behavior of armchair graphene ribbons both with a regular and an irregular distribution of antidots , its effect on transport was simulated by introducing a vector potential We have added to our code for the unction)  simulatielocity) ,19,54,65 A→=Bxy^ .x, the condition on the longitudinal invariance of the vector potential within each section translates into a limitation on the magnetic flux threading each section, which has to be much less than the flux quantum. Therefore, we have to divide the device into a large number of thin sections.We compute the transmission matrix of the device using a recursive scattering matrix technique . We subdx of all the physical and geometrical parameters, within each section the four envelope functions of monolayer graphene x and of a transverse component depending only on y: e is the elementary charge; h the Planck constant); E is the injection energy; Due to the invariance along uivalent ,67 to thdomain 0,W˜)(1)φ→domain 0,W˜)(1)φ→A and B of the four envelope functions at the interface between neighboring sections, we have computed the scattering matrix of the transverse region containing this interface [t. The conductance G and the Fano factor F  have been obtained using the Landauer–Büttiker approach:Then, by enforcing the continuity on the two graphene sublattices nterface . FinallyThe number of transport modes considered in the calculation was chosen in such a way that a further increase of this number would not alter the transport results within a given accuracy.At the entrance and at the exit of the considered nanostructure, we have included two regions with low potentials, which emulate the effects of the input and output contacts and guarantee the injection of a sufficient number of propagating modes into the ribbon.The correctness of the presented approach has been confirmed by performing some tests also with the alternative gauge Equation  with a nWe have also used our code to simulate the results of a conductance measurement on a nanopatterned graphene nanoribbon that is available in the literature. In reference  a 100 nmeference  yields gx and y directions) by a random quantity uniformly distributed between In order to obtain an aspect ratio among those commonly used in experiments and an overall size yielding a problem of manageable computational complexity, we have considered a 110 nm wide and 200 nm long armchair graphene ribbon (corresponding to a width of 894 dimer lines) containing a set of circular antidots, all with a radius of gion see . We haveE: 0.02, 0.1 and 0.3 eV) the conductance  ,46 and bis case) ,33,34. SE for several values of the magnetic field, for the cases of ordered and disordered antidots. We see that, starting from an energy gap of the order of 0.06 eV for In order to analyze the effect of the magnetic field on the energy gap, in ferences ,62 for uWe notice that this agrees with the behavior . In the absence of confinement, for high values of the magnetic field B the electrons can propagate only through the Landau state with E. Therefore, for high values of B the conductance is equal to B, the Landau levels decrease and therefore the number of propagating modes increases. When B reaches the value Now let us focus on the values of energy and magnetic field for which the sample has a nonzero conductance. In particular, let us consider the behavior of the conductance as a function of the magnetic field obtained for E , because a semi-classical approximation is accurate if the Fermi wavelength is sufficiently small with respect to the geometrical feature sizes of the device. As a rule of thumb for the validity of the semi-classical approximation, we can compare [A is the area of the antidot lattice unit cell) due to the Aharonov–Bohm interference between the components of the wave function scattered by an antidot [When the antidots are present, the behavior is less regular and several minima and oscillations appear. These features can be explained with the effects studied in GaAs/AlGaAs  heterostructures in reference  and in girection . This ap compare  the Fermdots see a, it givdots see a for B=8 antidot .B, we notice that for large enough B the effect of the antidots vanishes. Indeed, for the energies and magnetic fields for which an energy gap is not present, from a semiclassical point of view the motion of the charges can be described in terms of cyclotron orbits. By increasing the magnetic field B, the cyclotron radius Finally, let us look at the conductance and noise behavior for high magnetic fields (which represents the main focus of this work). By examining the behavior of the conductance as a function of the magnetic field E/(evFB)  decreasetructure b withoutWe have presented an extension of our envelope-function simulator with the inclusion of a mass term (in order to define regions in which particles cannot penetrate) and of the effect of magnetic field, in order to study the transport and noise behavior in an armchair graphene ribbon of a realistic size, with an antidot lattice and an orthogonal magnetic field. We have observed that, as for a graphene sheet, in the case of a confined perforated graphene structure, the energy gap decreases as the magnetic field is increased. Moreover, our results show that, as could be expected from the analogy with ordinary disordered semiconductors, for high values of the magnetic field, the effects of the antidot lattice on the conductance and noise behavior of the structure vanish, as a consequence of the formation of the edge states moving along the boundaries of the structure. In such conditions, transport becomes ballistic and shot noise vanishes. Therefore, such an effect is insensitive to the particular nature of the material. From the point of view of the application of graphene-based devices to digital electronics, nanopatterning with an array of antidots does indeed lead to a gap significantly larger that the one achievable by means of lateral confinement alone; however, the antidots act also as scatterers, thereby lowering the maximum achievable current and therefore the resulting effective mobility. Thus, the antidot density and layout must be chosen carefully, as a result of a trade-off between gap opening and conductance suppression. Our simulation approach and the presented results can be of assistance in establishing such a trade-off, and, in general, in the design and optimization of graphene-based devices and sensors operating in the presence of magnetic fields.


The design and fabrication of a new effective manufacturing method of heteroatom-doped carbon materials is still ongoing. In this paper, we present alternative and facile methods to obtain N-rich graphene with the use of low energy gamma radiation. This method was used as a pure and facile method for altering the physical and chemical properties of graphene. The obtained materials have an exceptionally high N content—up to 4 wt %. (dry method) and up to 2 wt %. (wet method). High-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectra and X-ray photoelectron spectroscopy (XPS) studies allowed us to evaluate the quality of the obtained materials. The presented results will provide new insights in designing and optimizing N-doped carbon materials potentially for the development of anode or cathode materials for electrochemical device applications, especially supercapacitors, metal–air batteries and fuel cells. Nitrogen atoms are exclusively bonded as quaternary groups. The method is expandable to the chemical insertion of other heteroatoms to graphene, especially such as sulfur, boron or phosphorus. Graphene has recently attracted the attention of the research society as well as industry circles. It belongs to the materials category called nano-carbons and particularly to the 2D class of materials. Theoretically, pristine graphene comprises only carbon atoms with some hydrogen atoms at the edge of each graphene plane. The description applies to paternal graphene planes as defined in the materials science encyclopedia and IUPAC documents ,2. Howev3 [Thus, facile and high-yield methods are explored for N insertion to carbon matrixes  since graphene’s chemical reactivity is limited. On the contrary to graphene oxidation, which is relatively easy to perform and has been known for a long time by standard wet chemistry oxidants like KMnO3 , the nit3 ,25,26  like carbon black, pyrolytic chars and activated carbons, in which heteroatoms may appear due to their transfer from a source material upon carbonization. Another way of heteroatom insertion is based on the presence of some surface reactive centers on amorphous carbon surfaces . Graphene hardly undergoes such heteroatom modification scenarios. Therefore, any method enabling the insertion of heteroatoms has a practical meaning. This fact points out the importance of the research concept presented in this paper.The morphology details of representative materials and pristine graphene nanoplatelets are shown in the SEM and HRTEM images . Figure The elemental composition for the N-doped graphene samples are given in 2/g. The high surface area is achieved due to the diminishing size of graphene plates (single and π-π stacked). Size diminishing means an increase in reactive centers located at the edges of graphene sheets. For smaller sheet the ratio: number of edge atom-to-mass is higher and therefore better for processes exploiting the reactivity of outer carbon atoms. Due to the same reasoning, the intensity of N-doping for the 150 nanoplatelets series (150 m2/g) is less spectacular. Elemental composition regarding C content in pristine (raw) nanoplatelets is inconsistent with their surface area. Lower C-content of 150/750 series in comparison to 300 series is a sign of the natural reactivity of the material exposed to air/oxygen even at room temperature. The highest C-content for 300 raw nanoplatelets is expectedly accompanied by the lowest O-content bonded to graphene planes as a result of a spontaneous reaction between carbon (graphene) and oxygen atoms (air).Graphene nanoplatelets of the 750 kind are the most susceptible to N-doping by gamma radiation despite of the type of doping approach (“wet” or “dry”). The value 750 is the level of average surface area, which in this case is close to 750 mThus, the 300 platelets are the less reactive material among all graphene platelets under investigation. The assumed highest chemical stability for 300 nanoplatelets resulted in the lowest susceptibility to N-doping even in the experimental conditions conducive to chemical reaction (gamma irradiation).The “wet” and “dry” methods differ because of the triggering of co-reactivity to oxygen. In both methods, oxygen is present in the reaction space: atmospheric oxygen (“dry” method) and water included oxygen (“wet” method). The mentioned difference applies to the case of the most reactive material, i.e., 750 nanoplatelets treated with 3D dose, where the oxygen content increased to the range of 12.395–14.72% O (“wet” method) from 11.09% O for pristine material. A similar phenomenon did not occur for “dry” method, when a slight decrease in O-content might be observed upon doses 1D, 2D and 3D.All gamma radiation-treated samples are characteristic because of very high C-content, which is definitely better than that for graphene oxide (C/O 1.5–2.5). The C-to-O mass ratio is differentiated regarding the doping method and the nanoplatelets kind.Raw graphene: 12—150 platelets, 85—300 platelets, 8—750 platelets.“Dry” method: 16–85—150 platelets, 18–95—300 platelets, 8–9—300 platelets.“Wet” method: 12–14—150 platelets, 13–45—300 platelets, 6–7—750 platelets.C/O ratios for gamma irradiated 750 nanoplatelets (“dry” method) are on average similar to C/O ratios measured for pristine graphenes. C/O ratios for “wet” method modified platelets are the lower than for raw graphenes and lower than corresponding values for materials subjected to “dry” treatment. Thus, the “wet” method beside N-insertion doubtlessly leads to oxidation of graphene matrixes as a side (unwanted) effect.The XRD diffractograms of the obtained materials are shown in −1 and corresponds to the tangential vibrations of carbon atoms. Thus, G peak intensity may be a good measure of a sample’s graphitization. N-doped graphene exhibits two strong characteristic bands at 1340 cm−1 (D band) and 1580 cm−1 (G band). These bands are characteristic for graphene [The Raman spectra (532 nm laser) of the obtained materials are shown in graphene ,43. In tD/IG) depends on the level of the disorder. The ID/IG ratios for GF_150 series are between 0.23 and 0.50, for GF_300 series are between 0.45 and 0.70, and for GF_750 series are between 0.58 and 0.94, respectively, as shown in D/IG ratio clearly demonstrates the defects in the graphene structure. The differences in the ID/IG ratios for three obtained series confirm that the materials contain a different number of defects in the carbon structure.The ratio of the intensities between the D and G bands  investigations. Typical N-insertion methods reviewed in the introduction are characteristic because of diversification of N atoms bonding to graphene matrixes. Several structures are typically assumed: quaternary, pyridine, pyridone, amine, pyroll, imid, amid, lactam, among which quaternary groups are of primary importance for electrode-based applications . XPS studies were aimed at the detection of the chemical environment of inserted N atoms.2 hybridized atoms (band C 1s at binding energy 284.6 eV), which is characteristic for graphene materials. The C1s spectra of N-doped graphene are composed of seven peaks corresponding to: C=C bond (sp2) peak at 284.6 eV [3) peak at 285 eV [The XPS spectra of the two representative samples of investigated series were determined and are demonstrated in 284.6 eV , C–C bont 285 eV ,45, C–O–t 285 eV ,41, C=O t 285 eV ,45, O–C=t 285 eV , and peat 285 eV . The tott 285 eV ,45,47. It 285 eV ,45, respt 285 eV ,51,52,53Sliwak et al.  reportedGamma irradiation causes the formation of reactive sites in the carbon matrix of an ionic and/or radical nature. In the obtained systems, the carbon matrix is directly enriched. This means that the enrichment of graphene in heteroelements can be obtained after the production of a porous graphene matrix. The proposed methods are characterized by a negligible consumption of reagents and a negligible amount of waste.3 aq  to each container and the contents were well mixed, and the containers were closed. Then, we inserted the containers into a radiation device.N-doped graphene was synthesized in two ways. In the first method called the “dry method”, 1g of graphene nanoplatelets  purchased from Sigma Aldrich was opened in a container containing ice. This was caused by the fact that the boiling point of this substance is 17 °C. Next, 10 mL of ethylamine was placed in a separate and open test tube. All test tubes were sealed in a square transparent plastic box. Then, we inserted the box into a radiation device. In the second method called the “wet method”, 1 g of graphene nanoplatelets (three different series) purchased from Sigma Aldrich were added to 100 mL PVC containers . Next, we added 25 mL 6M NHIrradiation was carried out in a radiation device RChM-γ-20, where the source of gamma radiation is Co-60. The dosing rate during the experiments ranged from 19.3 to 21.0 Gy/h, average value ~20 Gy/h, determined using a Fricke dosimeter. Periodically, further samples were taken for analysis in a specified time schedule. After each irradiation step, the material was washed repeatedly with distilled water (2 L) using a Büchner funnel  to remove all impurities, in particular, the residues of ethylamine and ammonia. Then, it was dried in an electric furnace at 150 °C for 24 h.2/g; 300—graphene nanoplatelets with an surface area of 300 m2/g; 750—graphene nanoplatelets with an surface area of 750 m2/g), Y means the method used , and ZD means the dosing rate for dry method  and for wet method . GF_X_raw—means raw material before processing.The N-doped graphene samples obtained by the proposed methods were denoted as GF_X_Y_ZD, where: e.g., GF_X means the type of used raw material , were used. X-ray diffraction (XRD) patterns of the samples were obtained with an X-ray diffractometer  equipped with a Cu Kα source at 40 kV and 30 mA. X-ray photoelectron spectroscopy  measurements were performed using a monochromatic Al Kα x-ray source. Survey spectra were recorded for all samples in the energy range of 0 to 1300 eV with a 0.5 eV step, high-resolution spectra were recorded with a 0.1 eV step.The morphology of the N-doped graphene was analyzed by scanning electron microscopy . The obtained materials were also examined by high-resolution transmission electron microscopy . The carbon materials obtained prior to the HRTEM microscopic analysis were dispersed in ethanol and treated with an Inter Sonic IS-1K bath for 15 min and deposited on holey carbon-coated copper grids. The volumetric elemental composition  of the materials was analyzed by means of a combustion elemental analyzer . Raman spectra were obtained by a micro-Raman spectrometer . The laser was tightly focused on the sample surface through a 50× microscope objective. To prevent any damage of the sample, excitation power was fixed at 2 mW. The resolution was 4 cmIn summary, we have demonstrated new alternative methods and a low-cost strategy for obtaining N-rich graphene. The N-doped graphene was successfully prepared using gamma irradiation at a radiation dose lower than 30 kGy. The most efficient method is the “dry method” with the use of ethylamine, where the nitrogen content exceeds 4 wt.%. The irradiation method is very selective regarding the chemical form of inserted N atoms, which are exclusively bonded as quaternary groups, i.e., functional groups exceptionally useful for the improvement of such doped graphene electrodes in batteries and supercapacitors. On the contrary, traditional N-doping methods yield very diversified forms of N bonding, among which only few are expected to be used in the mentioned electrochemical applications. The proposed methods are a simple and universal option to the already known methods of introducing nitrogen and other heteroatoms, such as sulfur, boron or phosphorus.This aspect of the performed study will be continued in further research. The future work should concentrate on two basic directions.Firstly, the influence of raw graphene structure on the qualitative and quantitative effectiveness of N-enrichment should be investigated. In this study, mostly MLG was investigated which meant that any of the applied N-bearing reagents had limited access to the reactive centers induced by gamma radiation in the intrinsic spaces inside the MLG granules. The authors assume that there might be a substantial difference whether SLG, FLG or MLG is subjected to the nitrogen enrichment according to the radiation procedures presented in this study. The less agglomerated graphene precursors like SLG or FLG should react intensively, yielding graphene-based materials of a higher N content than in the case of MLG. For this purpose, several graphene splitting methods seem to applicable like electroexfoliation combined with the wet-chemistry exfoliation by means of polar aprotic liquids . Intensively electroexfoliated graphene will be investigated as a continuation of the current study, which can serve as a reference point.Secondly, the discovered unified chemical bonding of nitrogen to graphene matrix should result in the advancement of the electrochemical properties of them. Therefore, such gamma radiation-modified graphene-based materials should be evaluated electrochemically as an electrode material in some batteries such as metal–air ones. Oxygen reduction reaction (ORR) will be investigated aiming at the determination of cathodic properties of the materials.Thirdly, there are neither theoretical nor experimental obstacles against nitrogen enrichment of other carbon-based materials like carbon nanotubes and even ordinary activated carbons. Nitrogen-rich activated carbons are still an emerging field in the search for effective electrode materials for plenty of electrochemical devices like metal–air batteries, supercapacitors, and fuel cells.


In this research, by utilizing the Very-High-Bond (VHB) 4905 elastomer, we carry out an experimental examination on the humidity effect on dynamic electromechanical performances of dielectric elastomers, including the dynamic response and viscoelastic creeping. Firstly, we experimentally analyze effects of the pre-stretch, peak voltage, waveform and frequency of the dynamic response of VHB 4905 elastomer under several ambient humidities. In general, the amplitude of dynamic deformation gradually adds up with the increasing humidity. Besides, it is found that the amplitude affected by different parameters shows diverse sensitivity to humidity. Subsequently, effect of humidity on the viscoelastic creeping of VHB 4905 is explored. The results demonstrate that, subject to different ambient humidities, the viscoelastic creeping under Alternating Current (AC) voltage is similar to that under Direct Current (DC) voltage. Furthermore, the equilibrium position of dynamic viscoelastic creep enlarges gradually with the humidity, regardless of voltage waveforms. For the dielectric elastomer with a pre-stretch ratio of 3, when the humidity increases from 20% to 80%, the increase of average equilibrium position of dynamic viscoelastic creep is larger than 1599%. Dielectric elastomers (DEs), a category of soft electro-active polymers, have gained much attention recently because of their excellent properties, such as high energy density, large deformability fast response and so on ,3,4,5,6.Nevertheless, the DEs are more widely used as dynamic actuators, and some researchers have analyzed the dynamic performances of DEs under constant environmental conditions. For example, Sheng et al.  proposedAlthough the above experiments have legitimately explored the humidity effects on static electromechanical properties of DEs and the dynamic electromechanical properties of DEs under constant environment conditions. However, too little work has been devoted to determination of the humidity effect on dynamic electromechanical properties of DEs. When the dynamic DE actuators in the moisture environment , the 3COOK), potassium carbonate (K2CO3), sodium bromide (NaBr) and potassium bromide (KBr), which are placed in the airtight container [In this article, under room temperature (20 °C), we investigate the humidity effect on the dynamic electromechanical properties of DEs, by applying an AC voltage. The electromechanical testing procedures are illustrated in ontainer . A high We vary the peak voltage , waveform, and frequency of applied voltage and pre-stretch ratio of VHB 4905 film under four humidity levels  in our experiments. Under different ambient humidities, we tested three pre-stretch ratios, three waveforms and four frequencies under the same nominal electric field. Furthermore, for each pre-stretch ratio , we also tested four different peak voltages. λp = 3, The voltage-induced dynamic deformation of VHB 4905 film under different ambient humidities is presented in λp = 2, λp = 3 and λp = 4), −1. It is noted that the amplitude increases gradually with the increasing humidity, especially when the humidity enlarges from 40% to 80%. Based on our previous research [λp = 2 to λp = 4. This can be explained as follows: a large pre-stretch stiffens the VHB film and limits a large deformation.For the VHB 4905 with three different equal-biaxial pre-stretch ratios  is investigated by using different peak voltages, which is displayed in λp = 2 and 1 kV~2.5 kV as the range of peak voltage for pre-stretch ratios λp = 3 and λp = 4. It is found that for a given pre-stretch ratio, the amplitude of VHB 4905 increases with the increasing humidity for all different peak voltages, and the high peak voltage greatly augments the amplitude of VHB 4905 with the increase of humidity, indicating that high peak voltage causes the dynamic deformation to be more sensitive to the humidity. This phenomenon may be due to the nonlinear characteristics of DE membranes, which is surely affected by the varying humidity.Next, using a sinusoidal voltage, the humidity effect on the amplitude of VHB 4905 under three equal-biaxial pre-stretch ratios , the humidity effect on the amplitude of VHB 4905 is investigated by using three voltage waveforms, which is displayed in Similarly, under three different pre-stretch ratios , the humidity effect on the amplitude of VHB 4905 is investigated by using a sinusoidal voltage with four different frequencies, which is illustrated in Finally, under three different pre-stretch ratios (λp = 3) when a sinusoidal voltage with a frequency of 1 Hz and a peak voltage of 2.5 kV is applied. Meanwhile, the effective DC voltage of the applied sinusoidal voltage is calculated, and the static deformation of the effective DC voltage is simultaneously measured. Under different ambient humidities, the increase of viscoelastic creep deformation for the VHB 4905 membrane under sinusoidal voltage is similar to that under the effective DC voltage. It is noted that the slopes of displacement-time curves are continuously declining, implying a gradually-weakened viscoelastic creep deformation of VHB 4905 elastomer. Based on these characteristics, it can be predicted that such creeping can be eliminated if the testing time is long enough. Similar results can be found when the triangle and sawtooth voltages are applied, which are shown in As is known, viscoelasticity is an inherent property of DE materials. In this section, we detect the humidity effect on the viscoelastic creep of VHB 4905 elastomer. We use the equilibrium position to evaluate the degree of viscoelastic creeping within the timescale of 198–200 s. The equilibrium position is defined as half of the sum of the peak value and valley value of the dynamic deformation. It can be seen, for each given voltage waveform, that the equilibrium position gradually increases with the increasing humidity, and the trend of increase is almost the same. From In this paper, we investigate the humidity effect on the dynamic electromechanical properties of VHB 4905 elastomer. Firstly, the effect of humidity on the dynamic response of VHB 4905 is explored. In general, the amplitude of dynamic deformation gradually increases with the increasing humidity. Among them, there are a variety of parameters that play distinct effects on the dynamic electromechanical performance of DE, such as pre-stretch, peak voltage, waveform and frequency. The amplitude is highly sensitive to the change of humidity at low pre-stretch ratio, high voltage peak value and low frequency. However, the amplitude under the random voltage waveform is less sensitive to humidity. In the following, the effect of humidity on the viscoelastic creeping of VHB 4905 is investigated. For different ambient humidities, the viscoelastic creeping is consistent when the DEs are under sinusoidal voltage, triangular voltage, sawtooth voltage and corresponding effective DC voltage. The experiment also analyzes the equilibrium position of viscoelastic creeping. For each given voltage waveform, the equilibrium position gradually rises with the increasing humidity. For the DE with a pre-stretch ratio of 3, when the humidity increases from 20% to 80%, the average equilibrium position of dynamic viscoelastic creep increases by 15.99 times. These investigations offer a strategy to comprehend the polyacrylic DEs for performance improvements and device explorations in some extremely moist environmental conditions. For future research, we hope to establish a dynamic model of the DE actuators incorporating the humidity effect.


Photothermal therapy is an emerging method of cancer treatment in which tumors are ablated by heating agents using near-infrared light (700–1000 nm). A semiconductor with a band gap between 0.3–0.7 eV would therefore efficiently emit near-infrared light. The new “magic” material graphene has a band gap of zero, which is advantageous with regard to designing a new material with a suitable band gap for the emission of near infrared light. In our investigations, using the first principles density functional theory calculation method, we aimed to and successfully designed graphene-based materials with a direct band gap of 0.68 eV. They have the potential to be optimal and efficient near-infrared light sources, due to their narrow yet fitting band gap. The present results open up a new avenue for the application of graphene-based materials to assist in photothermal therapy. Biomedical engineering; Materials chemistry; Materials science; Oncology; Physical chemistry; Photothermal therapy; Band gap; Graphene; First principle calculation. The Photothermal therapy (PTT) is less damaging among other cancer treatment methods largely due to its creative use of heat . This apin vitro drug delivery as well as in vivo cancer treatment using a near-infrared laser source [Graphene has various potential applications in the biomedical field . In recer source . Moreover source , 20.This indicates that graphene oxide is an effective photothermal agent with an absorbance ability which is comparable to that of gold nanoparticles and carbon nanotubes . HoweverIn this research, we used first-principles calculations to tune the band gap of graphene-based materials using the method of doping with different elements. In order to achieve the band gap within the aforementioned range to emit near infrared light , we depoOur first-principles calculations, based on the density functional theory (DFT) method, are discussed in Section 2We performed first-principles calculations based on the DFT , 26, 27 The ABINIT  package −10 Hartee/Bohr. Structural optimization was performed using.The convergence criterion for total energy calculations in the self-consistent field (SCF) iterations were set to 10−6 Hartree/Bohr.Broyden-Fletcher-Goldfarb-Shanno method (BFGS)  and the First of all, we needed to perform convergence for kinetic energy cutoff, k-point mesh and vacuum height. The convergence criterion for the total energy were less than 0.0001 Hartree for two consecutive SCF cycles. In order to deposit impurities on top of a graphene sheet, we used the above mentioned converged kinetic energy cutoff, k-point mesh and vacuum height values to perform optimization. The atom position and the size of the unit cell were relaxed until the equilibrium state was reached. In the next step, we used all the above-mentioned converged parameters and optimized the atom position and unit cell to calculate the converged charge density for the future band structure calculations.1, a2, a3 are the real space lattice vectors.The 3D Bravais lattice is expressed using the real space translational vector:1, b2, b3 are the reciprocal space vectors.The corresponding reciprocal space translational vector G can be expressed using:In order to perform band structure calculations, the first step was to compute the self-consistent total energy so all k-point sets could be calculated automatically with the.Monkhorst-Pack scheme . The resWe first have performed calculations of the atomic structure and band structure of pure graphene with the slab model and converged vacuum height. We used 2 × 2 supercell to calculate graphene doped with oxygen , boron , nitrogeGraphene was interstitially doped using oxygen, boron and nitrogen. Each element was deposited on three typical doping sites, with either the doping element located directly on top of a carbon atom (T-site), at the center of a hexagonal (H-site) or the midpoint of a C–C bond (B-site); all three positions are shown in Additionally, graphene was substitutionally doped using germanium, tin, and silicon elements.λ represents wavelength and c is the speed of light. For a given frequency, the band gap is represented by Eλ. In near-infrared light, the wavelength is 700–1000 nm and the corresponding band gap is 0.34–0.73 eV.The relationship between band gap and the color of light is given by the following equation:3Before relaxing the lattice vectors, we performed convergence calculations to obtain the most accurate energy cutoff, k-points and vacuum value for each element. In −5 Hartree/Bohr. The optimized lattice constants are listed in We used oxygen, boron, nitrogen, germanium, tin and silicon to dope pure graphene. For our elements using interstitial doping, oxygen, boron and nitrogen, we have selected three typical positions for each dopant material, so in total, we have optimized nine atomic structures. In addition to the interstitial doped materials, we have optimized three structures using substitutional doping for germanium, tin and silicon elements. Using our previously converged values, we optimized the lattice constant and atomic positions for all of the doped graphene materials with the criterion requiring 1.0 × 10In order to perform band structure calculations, we have first performed total energy calculations for all the materials. Using the three converged values, the kinetic energy cutoff, k-point mesh and vacuum height as well as the optimized lattice constants and atomic positions, we performed total energy calculations, resulting in obtaining the converged charge density. Using the converged charge density, we performed non-selfconsistent band structure calculations for the nine materials. In the final step, utilizing all the values we had obtained thus far, we plotted the band structure and calculated the band gap of each material. For the doped materials, we chose the smallest of the band gaps out of the three sites  that still fit in the ideal range. The results are presented in In Figures 4Photothermal therapy needs a specific band light to excite a photosensitizer to a state where it is able to absorb vibrational energy in order to ablate the target tumor. Nanomaterials have been prime candidates in photothermal therapy as ablation agents to convert light to heat, due to their optimal optical absorption and electrical capabilities , 41. In In order to save experimental resources, theoretical calcations are required. Prior to an elevated concentration of attention and resources with respect to manufacturing materials for photothermal therapy, it was necessary to first optimize potential nanomaterials. Our research engineered twelve potential nanomaterials through doping, nine of which utilized interstitial doping and three of which utilized substitutional doping. Oxygen-, boron-, and nitrogen-doped graphene, each doped at the H-, B-, and T-site, constituted the nine interstitially doped materials, where a dopant atom was deposited on a graphene layer. Tin-, germanium-, and silicon-doped graphene constituted the three substitutionally doped materials, where a carbon atom was replaced with a dopant atom within the graphene structure. Boron doped graphene at the B- and T-site proved suitable as a nanomaterial to convert light to vibrational energy for tumor ablation, with band gaps of 0.69 eV and 0.68 eV respectively, fitting in the optimal range of 0.3–0.7 eV, in excellent agreement with previous calculations . The ideSince photothermal therapy operates through using near-infrared light lasers to ablate tumors on a patient, this method will most likely remain an option for malignancies near or on the surface of a cancer patient's body. However, if a more invasive tactic is needed due to tumors in the depths of a body cavity, photothermal therapy reaches its apex of effectiveness when used before or in conjunction with chemotherapy , 44 and Photothermal therapy is a relatively new and innovative treatment for many conditions, primarily cancer. The main obstacle hindering photothermal therapy from becoming a common and reliable treatment for cancer in the healthcare industry is the inefficient and inconsistent ability of materials used in the involved procedures. Using the knowledge of existing potential materials in the scientific sphere and theoretically engineering and testing compounded products, a choice nanomaterial to streamline the procedure of photothermal therapy will certainly be discovered. The breakthrough of photothermal therapy as an emerging treatment in the medical field will renew the simple and effective concept of utilizing heat to attack malignancies, bringing a non-invasive and less risky method into the realm of cancer treatment.5A wide range of materials have been introduced into the testing of photothermal therapy, depicting the high potential of this non-invasive and emerging cancer treatment. With the wonder material, graphene, as the base of our twelve nanomaterials, the potential for a successful ablation agent is large. Through our DFT calculations within the Abinit computational program suite, we found boron-doped graphene to be an unexpected but possible contender as an ablation agent in photothermal therapy, resulting in a band gap of 0.69 eV at B-site and 0.68 eV at the T-site. The band gap of boron-doped graphene matched the wavelength of near-infrared light, deeming it as an effective convertor of vibrational energy. As a possible ablation agent, boron-doped graphene holds many possibilities. Ablation agents in photothermal therapy require further evolvement to become multifunctional, as a drug carrier or contrast agent. In conclusion, our research serves to primarily theoretically optimize the chosen materials to be used in photothermal therapy, to save resources and money for the future of this treatment, prior to serious testing. Our research also serves the purpose opening a new avenue in the search of an ablation agent through the doping of graphene to create unique nanomaterials, which comprise a vast range of possibilities regarding the future of the medical field.The raw/processed data required to reproduce these findings can be available via special request to the author.Faith Cheung: Conceived and designed the experiments; Performed the experiments; Analyzed and interpreted the data; Contributed reagents, materials, analysis tools or data; Wrote the paper.This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.The authors declare no conflict of interest.No additional information is available for this paper.


It hinders native nucleation centers and breaks the propagation of defects through the layers, protecting from prolonged exposition to all common solvents found in biochemistry work, contrary to commonly used polymeric passivation. Since wet etch does not allow the required level of control over the lithographic process, a reactive ion etching process using a sacrificial metallic stopping layer is developed and used for patterning the passivation layer. The process achieves devices with high reproducibility at the wafer scale.This work is on developing clean-room processes for the fabrication of electrolyte-gate graphene field-effect transistors at the wafer scale for biosensing applications. Our fabrication process overcomes two main issues: removing surface residues after graphene patterning and the dielectric passivation of metallic contacts. A graphene residue-free transfer process is achieved by using a pre-transfer, sacrificial metallic mask that protects the entire wafer except the areas around the channel, source, and drain, onto which the graphene film is transferred and later patterned. After the dissolution of the mask, clean gate electrodes are obtained. The multilayer SiO Since first obtained by the exfoliation of graphite , graphen2O3 or SiO2 film [Graphene is a zero bandgap material that generates electrons and holes under an applied transverse electric field, which is a process known as electrostatic gating . TherefoiO2 film . In thisiO2 film ,11.EG-GFETs are commonly built without the reference gate electrode , which ix) and silicon oxide (SiO2) layers [2 is much more permeable to ions than SiNx. A higher permeability may allow ions from the test solution to reach the current lines and cause drift, cross-talking between electrodes, or corrosion of the metallic contacts [When designing EG-GFETs, it is crucial to consider their application, e.g., the device’s environment, to decide design and fabrication steps. Electrolyte gating implies using liquids on top of semiconductor materials that typically degrade upon contact with aqueous solutions. Moreover, both semiconductor and dielectric materials are prone to host ions that diffuse inside their lattice, degrading the materials or rendering electronic measurements unstable. Therefore, the passivation of all surfaces in contact with the electrolyte, except graphene, is recommended to prevent/minimize such effects . The pas) layers ,14. An a) layers , reduce ) layers , reduce ) layers . Thus, w) layers  to avoidcontacts .2 or SiNx layers allows exposing the devices to all solvents without compromising the passivation. However, it implies more complex lithographic and etching processes, thus increasing the fabrication cost. In conclusion, it is of paramount importance to keep in mind the application of the EG-GFET when designing the passivation of current lines.While using epoxy resins such as SU-8 negative photoresist provides a relatively inexpensive and straightforward process, it imposes a limit on the use of strong solvents in contact with the fabricated devices. For example, dimethylformamide (DMF) as a graphene cleaning agent after wafer fabrication and as a solvent in the graphene’s non-covalent functionalization  would noAn important consideration is to decide at which point of the fabrication process the passivation layer should be added. Overall, lithographic processes involving aggressive patterning steps  should be avoided once graphene is transferred onto the wafer since they increase the amount of residues left on graphene . Therefox/SiO2, the process implies more aggressive steps, e.g., plasma-based etching or sputtering depositions that can affect graphene integrity [Passivation based on photoresists is done in a relatively straightforward process, using one lithographic step only followed by development in solution (a mild process) and sometimes a final bake to harden the layer. However, for passivation based on SiNntegrity . Some auntegrity . HoweverDependence on wet etch processes always limits reproducibility and process upscaling . There aAnother critical step in EG-GFET fabrication is the graphene transfer. For applications requiring electronic grade material, there are few choices available beyond mechanically exfoliated graphene from highly oriented pyrolytic graphite (HOPG), Chemical Vapor Deposition (CVD) being one of them . Still, Although wet transfer methods of CVD-grown graphene give the most promising results for the large-area fabrication of GFETs, there are still challenges related to surface contaminants ,26 oftenMaterials used for microfabrication of EG-GFETs are listed in Confocal Raman spectroscopy  is used to confirm single-layer graphene presence in transferred samples and detect variations in graphene quality after microfabrication processes. Raman data analysis is done using WITec Project FOUR+ software, Ulm, Germany. All samples are analyzed using a 532 nm Nd:YAG laser for excitation. The laser beam with power in the range 2 to 3 mW is focused on the sample by a ×50 lens , and the spectra are collected with a 600 groove/mm grating using 5 acquisitions each with 2 s acquisition time. Within each experiment, the laser power is fixed to allow comparison of the acquired data.Scanning Electron Microscopy (SEM), FEI NovaNanoSEM 650, Hillsboro, OR, USA, is used to study surface features and energy-dispersive X-ray spectroscopy (EDX) analysis. SEM images are collected in the secondary electron imaging mode at a 5 mm working distance and an operating voltage of 5.0 or 10.0 kV, depending on the materials to be analyzed and the probing depth desired. EDX acquisition using Oxford Instruments INCA software, Oxfordshire, UK, is performed on selected regions from SEM images to confirm surface chemical composition and detect surface contaminants after completing the fabrication process.2 plasma-based etching steps.KLA—Tencor P-16 Surface Profiler, Scotia, NY, USA, is used to measure photoresist films’ step height after O2 and SiNx films’ thickness, using a deuterium–tungsten halogen light source. The thickness is determined by fitting to a model using reflected light between 40 and 800 nm.OPM Nanocalc—Optical Profilometer/Interferometer, Ettlingen, Germany, is used to estimate SiONikon Ni-E optical microscopes, Tokio, Japan, are used to visually assess the sample surface after each of the fabrication steps.SD), and the source–drain current (ISD) is measured. The high-impedance gate circuit is formed between gate and source contacts. It is biased by applying a voltage (VGS) by a Keithley 2400 source meter, Cleveland, OH, USA, which is programmed to apply voltage ramps from 0.2 to 1.2 V in steps of 0.01 V. All the measurements were performed using 10 mM phosphate buffer as gate electrolyte to close the circuit.For acquisition on the transfer curves of the fabricated EG-GFET samples, the source and drain contacts of each transistor are connected to a Keithley 4687 Picoammeter, Cleveland, OH, USA, which applied a constant (1 mV) source–drain voltage  and measuring the channel’s current, using a Keithley 2400 source meter. No liquid electrolyte is added to the devices, and no gate voltage is applied (the gate contact is left floating). Channel resistance values by the device are obtained by processing the current measurements using MATLAB scripts.In this study, graphene is grown by CVD in a hot-wall reactor  on high-purity Cu catalysts and transferred see . The pro3 solution that stay attached to the graphene film’s bottom side that stick to the surfaces to which graphene is transferred, as shown in 3 solutions and sequential dissolutions can improve the removal of Cu clusters. Regardless, small Cu atomic clusters and ions are always observed in the surfaces after graphene transfer, as shown by PIXE studies [Graphene transfer and patterning are crucial steps in the fabrication of graphene devices. Except for automated, continuous transfer systems , which a studies . Those p studies ,31. This2 partial pressure since they influence the etching efficiency and the exposure time that the photoresist can sustain. However, the process is dependent on the size of the etched area. For example, etching small substrates with a few tens of square centimeters is very different in etching time and uniformity than etching a 200 mm-wafer due to changes in the plasma current at the surface of the sample [The most common way to pattern graphene is reactive ion etching, using an oxygen plasma that readily attacks and removes carbon . For dene sample ,33.2 plasma time indicate that the photoresist is etched much faster when using the ICP O2 reactive ion etching (RIE)  b than wha source a. ECR shConsidering the etching times allowed by both methods, samples with pre-patterned contacts and graphene are patterned. For the ECR plasma source, the sample is coated with AZP4110 at 2200 nm  to maximize the etch time. The sample is etched for a total time of 18 min divided into 6 min etching periods . For the ICP plasma source, the sample is coated with AZ1505 at 1035 nm  and etched for 10 s. According to the values in 2 plasma is also expected to remove graphene transfer-related residues  from the surface. However, the optimal time for graphene patterning without removing the photoresist is usually not enough to achieve good surface cleaning. The use of low ECR-power O2 plasma requires increased time of process. Still, it allows for improved control of the system temperature, improving photoresist stability, reducing at least 10 times in the photoresist etch rate. With longer times, organic residues’ removal from the surface is also improved, and graphene is efficiently etched from a full 200 mm wafer in less than 18 min. Therefore, in the following, ECR-O2 plasma is preferred whenever the dry etching of graphene is required.High power processes (above 1000 W ) are hig2 plasma etching is removing metallic particles or other non-organic transfer-borne residues. These residues that come adsorbed to the backside of graphene upon transfer are not removed by O2 plasma and hinder device performance, as detailed above. A more elaborate strategy is necessary, preventing direct contact between residues and chip surface. In the next section, a lift-off process is studied to limit the wafer surface’s contamination by debris resulting from the graphene transfer process.The limitation for ECR-OA lift-off inspired process could be an alternative to the standard dry etch patterning, allowing minimum contact of graphene with unnecessary/undesired regions of the surface and achieving a cleaner fabrication process. It is our experience that when transferring graphene over a surface with relatively steep steps (above 100 nm), the film likely breaks and tears apart (crack propagation) at the step region. Therefore, using a lift-off technique to transfer graphene only to the wafer regions where transistor channels form should be possible. For lift-off assisted wet transfer, a sample with gold contacts is spin-coated with photoresist (AZ1505 1035 nm or AZP4110 2200 nm) and patterned by optical lithography. The transfer region is left unprotected, as schematically shown in Graphene transfer is performed as described in the The optical images in The clear advantage achieved with the lift-off strategy is the final quality of the device surface. Based on the results of A test sample was prepared using 2200 nm AZ4110 photoresist for the lift-off assisted graphene transfer. After transfer and PMMA removal, inspection by optical microscopy accesses the quality of the patterning. Although the features were large and well separated, 2 plasma using a photoresist mask. Any contaminants not removed by the oxygen plasma are removed together with the hard sacrificial mask. The contaminants possibly deposited with graphene on the source and drain are not avoided. Still, they do not significantly affect the device performance, since they are not in contact with the biological solutions.The previous sections show that lift-off patterning graphene films produce inferior results compared to patterning standard materials by the same technique. Consequently, a novel methodology is developed, as schematically shown in 2O3 film was sputtered for physical separation of the Au surfaces from the sacrificial metal layers, avoiding inter-layer diffusion. Films with 10 and later 20 nm of Al2O3 were used to ensure this layer’s stability during aluminum etch (the etchant is the same for both Au and Al2O3). The next layer in the stack is AlSiCu, the protective layer that avoids residues to deposit on the devices’ surface. The capping layer is TiW(N) to allow all lithographic processes (the photoresist developer quickly dissolves AlSiCu and is too reflective for precise laser exposure). Al2O3 may replace TiW(N) as a capping layer to avoid repeated use of H2O2 to etch TiW(N), which increases the risk of damaging graphene , leaving the graphene intact. With that in mind, it was designed as follows: first, a buffer Alhene see .2O2 removes TiW(N), or AZ400k 1:4 developer removes Al2O3, depending on which material was used as the capping layer. AZ400k can etch both Al2O3 and AlSiCu, so it is used to etch the adjacent AlSiCu layer. The etch rate of AlSiCu is 10 times higher than that of Al2O3, so the etch time is adjusted to preserve the Al2O3 buffer layer. However, optical images after the process . This forces stopping the fabrication process, since gold is no longer protected.At the point of the fabrication sequence where the sacrificial layer is added, only the contacts have been patterned, and so a standard lift-off can be used with no risk of damaging underlying layers. Thus, after a lithographic step that leaves the photoresist protecting the source, drain, and channel, the sacrificial layer stack is deposited by sputtering followed by lift-off using acetone and ultrasonic bath. Next, graphene is transferred by wet transfer a, and PM2O3 thickness could improve this result. However, it is difficult to envision because Al2O3 needs to be later selectively removed  was deposited between the buffer layer of Al2O3 and AlSiCu. In this way, the wet etch of AlSiCu is accomplished with no attack on the Al2O3.A further increase in AlFollowing the above process, a new sample is prepared and observed with the optical microscope revealing spotless surfaces with well-patterned graphene transistors, as seen in 2O3 as a capping layer: partial removal of the sacrificial layer occurs upon graphene transfer  should be chosen, because the HCl residues do not degrade it. Then, it should be as thin as possible to reduce the photoresist/graphene exposure time to H2O2 during TiW(N) etch.A final comment on the use of TiW(N) or Altransfer  due to H2O2 30% 150 s, then AZ400K 1:4 240 s, H2O2 30% 50 s. This stack proved useful in avoiding residues in the gold gate electrode since, after this process, the Al2O3 film on top of gold is particle-free.For these reasons, the sacrificial layer stack was defined as TiW(N) 5 nm/AlSiCu 100 nm/TiW(N) 15 nm. The wet etch process to remove it was H2 and SiNx films with a total thickness of 250 nm is designed, starting with a layer of SiO2 to take advantage of the good adhesion of SiO2 to graphene and the substrate, and terminating with SiNx to take advantage of the superior impermeability of SiNx. The multilayer, deposited by plasma-enhanced CVD (PECVD), hinders native nucleation centers and breaks the propagation of defects through the layers, creating tortuous diffusion paths for water and other small molecules [Before designing the passivation layer, several points need consideration. First, consider the final use of the devices. In our case, a clean biosensing interface is obtained by the use of strong solvents   that attolecules ,36. All 2, each containing 36 chips of 20 EG-GFETs, were fabricated as described in For testing, samples of 4 × 4 cmSome reports refer to dry etching methods  to open First, dry etching is used to open the top layer of the passivation stack d. Many a2/SiNx stack delamination, as shown in 2 film under the SiNx during the KOH wet etch process, promoting the top layer’s stress release by peeling  . However2O3, AlSiCu, TiW(N), Al, Cu, and Ni), ranging from metals to insulators, are sputtered (RF or DC with low and high power) on top of several graphene samples. After sputtering, a wet etch of those materials is performed at room temperature and with mild agitation for all samples. Different etching agents are used to match the material to etch: AZ 400k 1:4 for Al2O3, AlSiCu and Al, H2O2 30% for TiW(N), and FeCl3 0.5 M for Cu and Ni. The etching process is stopped when the samples seem clean. The graphene quality of these samples is analyzed by Raman Spectroscopy before and after sputtering and wet etch. The comparison of Raman spectra for all combinations shown in We propose a specific solution, consisting of the insertion of a stopping layer between graphene and the dielectric to be etched see . When a 2O3, seems to induce the oxidation of graphene. The deposition of AlSiCu also induced many defects that could be originated by the high power plasma of the sputtering system with an additional contribution from mechanical damage during the dissolution of aluminum, where bubbling was observed. A similar situation occurs with TiW(N), where the etchant H2O2 30% leads to the complete oxidation of graphene. Then, a low power (100 W) sputtering system with a sizeable target-sample distance of 30 cm (larger than in the system previously used) was tested. While the RF sputtering of pure aluminum lead to the damage of graphene after its removal, the DC sputtering of Cu and Ni did not induce a significant increase in the Raman defects peak  at 2 kW and 1 kW, respectively, and RF sputtering of aluminum oxide at 2.5 kW were found to damage or altered the material extensively. The deposition of oxide films, such as AlInterestingly, these metals are also well-known catalysts for graphene growth, and their deposition on graphene was reported as healing graphene . Once grThe next challenge for the preparation of the stopping layer is patterning. Patterning by wet etch should be avoided if we are to precisely control the features’ size, and patterning by standard lift-off is limited, since ultra-sonication is forbidden due to the graphene underlayer. Therefore, the lift-off process was changed as follows. Soaking the photoresist with a TMAH-based developer  before exposure creates a top hardened layer that behaves differently upon exposure and development. Development occurs faster in the remaining photoresist than in the hardened layer, producing “mushroom hat”-like features, or a negative profile, which creates a shadow during metal deposition and, therefore, facilitates lift-off. Since this feature forms at the top photoresist surface, immersion in a solvent peels-off this layer, where the sputtered materials are adhered. Testing this methodology on samples with pre-patterned contacts and graphene was highly effective and reproducible even at a wafer scale.2 and three 50 nm films of SiNx with 250 nm of final thickness. The passivation stack is patterned using 1035 nm of AZ1505 photoresist and optical lithography, followed by RIE using previously optimized parameters. After removing the remaining photoresist, the channels and the gate electrode are released by wet etch of the stopping layer (AZ 400K 1:4 for AlSiCu and FeCl3 0.5 M for Cu or Ni). The removal of the stopping layer was followed by EDX, allowing the final devices to be process contaminants free. The EDX spectrum in Based on the presented results, samples with pre-patterned gold contacts were prepared to test the passivation patterning process by dry etching using the best protective stopping layers. Samples with gold contacts and graphene are prepared as follows: the samples are coated with 600 nm of AZ1505 photoresist and soaked in the developer (AZ400k 1:4) previously to optical lithography. After lithography and development, each sample is sputter-coated with copper  or nickel , which is followed by aluminum alloy  and titanium-tungsten (TiW(N), 5 nm). Then, the samples are immersed in acetone for 1 h at room temperature and then rinsed with an acetone wash bottle to promote the loose material’s release. The soaking method avoids sonication, preventing the damage/delamination of graphene. Next, the passivation layer is deposited as a stack of two 50 nm films of SiO2/SiNx passivation stack and the capping layer of TiW(N) and stops at the AlSiCu layer. The removal of AlSiCu by an alkaline solution (AZ400k) is confirmed in the spectrum of 2O3 that is beneath the Cu of the stopping layer. The spectrum confirms the removal of the Cu by FeCl3 0.5 M in 2O3 from the gold surfaces and showing no evidence of significant contaminants at the surface of the device.The RIE etching step etches away the SiOCNP) indicating intrinsic p-doping of the devices. We obtain a field-effect mobility for electrons and holes of μe ≈1700 cm2 V−1 s−1 and μh ≈1300 cm2 V−1 s−1, respectively, by fitting the transfer curves to a model describing the DC conductivity of single-layer graphene (SLG), σ, as a function of gate voltage. The model is based on carrier resonant scattering due to the strong short-range potentials originating from impurities adsorbed at the graphene surface [Confirming the results shown in  surface ,41.This study’s main goal is to develop a process for the wafer-scale fabrication of high electronic quality devices for biosensing applications. The final devices produced at the 200 mm wafer scale following the process proposed in this paper are resistant to all the solvents used for graphene functionalization  and have2O3 protective layer following the results of The first step is to open the back-gate access using optical lithography and reactive ion etching . Then, aThe sacrificial layer for graphene transfer is prepared by lift-off following The processed PMMA/graphene films are transferred onto the wafer’s desired regions until full coverage is achieved see  below. A2O3 is selectively removed to improve adhesion of the passivation to the chips’ surface. Al2O3 is kept only at the gate and pads to prevent contact with the stopping layer by patterning 2200 nm thick AZP4110 photoresist and wet etching with alkaline solution (AZ400k 1:4). A hard coating for passivation is chosen . The defect-related D mode ratio to the G mode changes from 0.12 (as-transferred) to 0.24 , but 2D/G ≈ 2.3, indicating graphene quality, is not significantly affected by the fabrication process.Optical images acquired after each fabrication stage  are usedR, below ≈1000 Ω is expected in successful devices, while values up to ≈2500 Ω are still acceptable. Transistors with R > 2500 Ω were rejected and discarded. Two wafers were processed and studied. Wafer A is a shared design wafer containing 9 × 18 chips . In R < 2500 Ω. The color code refers to four classes of data values according to quartiles, iq . The spatial distribution of the resistance values looks random, and no correlation with the graphene patches individually transferred (R6 (R5) to 617.96 Ω (816.83 Ω) for R9 (R10).For the devices’ electrical characterization, an automated probe station is used to measure either the current or the voltage drop in the channel between source and drain contacts at a fixed voltage of 1 mV or a fixed current of 1 μA, respectively. Then, the measured values are converted to resistances to provide information on the homogeneity of the devices’ process and quality . For the18 chips , each chnsferred  is visibnsferred  showing R > 5 kΩ were rejected (4704 − 4107 = 597). The x- and y-coordinates of each data point corresponding to one pair of resistors. The color code reflects four classes of data values according to quartiles, iq . A second wafer (wafer B) was processed and measured at constant source–drain current. A process for the fabrication of chips containing graphene electrolyte-gated FETs is developed step by step in this study, having in mind their application as biosensors. Many technical solutions for different process issues were suggested, developed, tested, and critically discussed. Some of them were rejected, given the study’s goal, since they do not provide chips with enough chemical or electrical stability. However, for less demanding applications, these solutions could be useful.Dielectric passivation as the final step of the fabrication process allows an improvement of signal stability. It decreases electronic noise, since only the graphene channel and the gate electrode become exposed to the electrolyte during measurements. One of the most relevant results to obtain a useful chemical-resistant chip is the possibility of metal sputtering on top of graphene films without inducing relevant damage. This result can be extended to devices where metallic layers are required on top of graphene without significantly increasing the fabrication time.A novel approach to improve the surface cleanliness of the chip surface after graphene transfer is demonstrated. An effective sacrificial layer is developed, allowing the patterning of graphene while protecting the pristine gold surfaces. This optimization is of high importance for using the devices as biosensors. It promotes better inter-device homogeneity and less random molecular adsorption responsible for the sensor signal’s random response and noise. The process is general and suitable for other applications or devices with similar requirements.This study casts light on the critical field of microfabrication of graphene devices for chemical sensors with electric transduction and their chemical stability as a function of the process chosen in a manner that allows researchers in the field to pick, among the results presented, those that better suit their application.


The synthesis of TiO2-NTs is performed using a hydrothermal process. Sample characterization is carried out using X-ray diffraction and scanning electron microscopy. The results show that the sensors can measure moisture values in the range of 5% to 95% with very high precision and very low hysteresis. The humidity variation between 5% and 95% shows a change in the sensor resonance frequency of ~3180 Hz, which is a significant change compared to many magnetoelastic humidity sensors developed so far.In this study, TiO Magnetoelastic materials change their shape when exposed to a magnetic field and, conversely, undergo magnetization changes when a mechanical stress is applied. This bidirectional coupling provides the transduction capability when working as sensing devices ,2,3,4. Igiven by ,6,7:(1)ΔE. coli [Salmonella enterica typhimurium [Magnetoelastic sensor platforms have been used for chemical and physical detection, including liquid density and viscosity ,12,13,14E. coli  and Salmhimurium ,34.2 nanotubes (TiO2-NTs) was coated on the MES surface in order to increase the surface area of MES and the humidity sensing properties of the prepared MES are reported. Although there have been some studies regarding the humidity sensing properties of TiO2-coated MES, in this study, we use TiO2 in its nanotube form for the first time and we present detailed results compared to previous studies.Jain  develope2-NTs was performed using a hydrothermal process. For this purpose, a TiO2 nanopowder was synthesized by a reflux method. Titanium isopropoxide Ti(OPri)4  as a precursor was dissolved in 2-propanol  for 2-PrOH/Ti(OPri)4:10 (n/n) and stirred for 15 min at 800 rpm at ambient temperature to form solution A. It contains mol/mol ratios of H2O/Ti(OPri)4 n/n = 10 and H2SO4/Ti(OPri)4 n/n = 0.01 were mixed homogenously by magnetic stirring and allowed to stand on a magnetic stirrer at 800 rpm for 30 min to form solution B. Solution A was added to solution B dropwise with continuous stirring at 800 rpm at ambient temperature for 30 min to ensure the formation of a homogeneous solution. The mixture was transferred to reflux at 110 °C for 6 h to complete the synthesized TiO2-NPs. Centrifugation was carried out to remove the solvents from the medium and dried at 80 °C in a vacuum oven for 8 h to achieve the anatase phase of titania. TiO2-NPs (2 g) were dispersed in 40 mL of 10 M NaOH ultrasonically, followed by hydrothermal treatment at 180 °C for 48 h in a Teflon-lined autoclave. The solid phase was then washed with 0.1 M HCl and distilled water at pH 6 to 7 and the subsequently filtered TiO2-NTs were dried at 80 °C for 8 h. The synthesis of TiOThe block diagram of the humidity measurement system is shown in A temperature sensor was placed into this unit and the temperature was monitored during the humidity measurements and no major temperature variation was observed during the testing. The humidity of the measuring unit was controlled using two flow meters, one flow meter controlling the dry air flow and the other humidified air, so that two humid and moisture-free gases were supplied to the measuring system at the desired rate and different humidity values were generated in the measuring system, the total flow rate usually kept constant to be around 400 sccm. The resonant frequency, frequency shift, and the mass change on the MES were measured using the homemade system. The measurement system can measure resonance frequency with 1 Hz sensitivity. All parameters during the measurements were controlled by a computer. 2-NTs was analyzed by X-ray diffraction (XRD) using a Rigaku RadB-DMAX II diffractometer with Cu Kα radiation (λ = 1.5418 A) in the region 2θ = 25.3°. For a description of the surface morphology, a Leo Evo 40 model scanning electron microscope (SEM) was used.The crystal phase of the TiO40Ni38Mo4B18) amorphous ferromagnetic ribbons was used as MES. The ribbons were cut with 30 mm long and 4 mm wide using a dice saw. All samples were cleaned in an ultrasonic bath with acetone and deionized ultrapure water. Afterwards, the ribbons were quickly dried. Then, a Cr film of 100 nm thickness and Au film of 100 nm thickness were coated on both sides of the ribbon using a thermal evaporator Vaksis-midas PVD/4T thin film system. Coated ribbons were then heated at 200 °C for 3 h to ensure good adhesion of gold. A thin layer of TiO2-NTs on the surface of the Cr-Au plated ribbons was formed using a drop-casting method. About 20 µL of TiO2-NTs in ethanol were dripped onto the surface of the plated ribbon using a micropipette. Ethanol was then evaporated and later, it was observed that TiO2-NTs were clustered on the surface of the plated ribbon, thus MES is prepared as a humidity sensor.2826MB 2, NaCl, KCl, and K2SO4 solutions have RH levels of 11%, 33%, 43%, 52%, 75%, 85%, and 97%, respectively. The different humidity levels using these salts were applied to BQ225 and DHT11, the humidity sensor and calibrations of these sensors were checked. Then, we have used BQ225 and DHT11 sensors to monitor the humidity level in the test chamber, so the variation of resonant frequency of TiO2-NT deposited MES as a function of humidity level was obtained (The TiOobtained .2-NT coated MES-1 was recorded as follows: First 5% RH then 95% RH was applied for some time and the cycle was thus continued. In addition, with the same sensor, 50% and 75% RH were cycled (All measurements were performed at ~26 °C. The humidification and dehumidification response time measured with the TiOe cycled . The sen2-NT coated MES-1 measured at different 77.5% and 95% RH levels. The sensor was continuously tested for ~15,000 s at 4 s intervals. It was observed that the free frequency response of the TiO2-NT coated MES was almost unchanged.The static humidity detection response of the MES-1 is shown in 2-NT-coated MES-1, MES-2, MES-3 and MES-4 for 5–95% RH cycles. Such a cycle for the MES-4 sample is shown in 2-NTs.2O3 was coated onto a 2826MB amorphous ribbon, and they tested the sensor at two different humidity levels, 2% and 98%. They found that the sensor shows a 500 Hz change in the resonance frequency for these humidity changes, and it takes approximately 2 h to obtain a steady-state response. Craig et al. [2 onto 2826MB amorphous alloys, and they found that stabilizing the sensor output for 60% and 2% RH level cycling takes about 30 min. In this study, the stabilization of MES-1 sensor output for 95% and 5% RH level cycling takes about 40 s, as it can be seen that the sensor response time in this work is much faster than that of previously reported magnetoelastic humidity sensors. However, it was also observed that the sensor response time increases with the increasing coated mass of TiO2. It should be noted that there are differences between previous studies [Magnetoelastic humidity sensors have been studied by Jain et al. . A thin g et al. ,18 also  studies ,18 and t2 film coated QCM sensor exhibited excellent humidity sensing performance in terms of higher sensitivity and shorter response/recovery time compared with the nanosphere and nanoflower TiO2 nanostructure [It has been reported that a hollow ball-like TiOtructure  since, atructure . Moreovetructure . We assuA number of methods have been developed for humidity detection, including capacitance ,40,41,422-NT film on Fe40Ni38Mo4B18 amorphous ferromagnetic ribbons was successfully fabricated using a drop-casting method. The effect of coated layer mass was reported for the first time for magnetoelastic sensor and different amounts of TiO2-NTs were coated on the amorphous ribbon and it was found that the resonant frequency change for 5–95% RH cycles increases with increasing mass of the coated TiO2-NTs. Furthermore, it has been found that these increases in the low coated layer mass are sharp and then this sharpness decreases. For the sample coated 2.64 µg of TiO2-NTs, a ~3180 Hz change in the resonant frequency was observed for variation humidity levels of 5–95% RH. The humidity sensing properties of the TiO2-NT film on MES is very sensitive to humidity changes and reversible adsorption/desorption performance, which is indicative of a good humidity sensor. In conclusion, a TiO


However, the easy restacking and volume expansion properties of SnS2 during the charge/discharge process lead to the destruction of the electrode structure and a decrease in capacity. We successfully synthesized a SnS2 nanocrystalline-anchored three-dimensional porous graphene composite (SnS2/3DG) by combining hydrothermal and high-temperature reduction methods. The SnS2 nanocrystalline was uniformly dispersed within the connected reduced graphene oxide matrix. The SnS2/3DG battery showed a high reversible capacity of 430 mAh/g after 50 cycles at 100 mA/g. The SnS2/3DG composite showed an excellent rate capability with the current density increasing from 100 mA/g to 2 A/g. The excellent performance of the novel SnS2/3DG composite is attributed to the porous structure, which not only promoted the infiltration of electrolytes and hindered volume expansion for the porous structure, but also improved the conductivity of the whole electrode, demonstrating that the SnS2/3DG composite is a prospective anode for the next generation of sodium-ion batteries.Tin disulfide (SnS The volume expansion effect (~420%) can cause damage as it leads to the serious pulverization of the crystal structure [2 materials could be mitigated by nanosizing to improve the electrochemical properties of SnS2 materials, such as SnS2 nanorods [2 nanosheets [2 nanoflowers [The demand for high-performance electrochemical energy storage and energy conversion devices is ever-growing ,2,3. Altndliness . The octs forces ,11. The tructure ,13. Resenanorods ,15, SnS2nosheets ,17, SnS2oflowers ,19, etc.2 [2 nanosheets as the van der Waals force between adjacent layers of SnS2 is destroyed by graphene, which is favorable for the electron transfer rate [2 as the SIB anode, various structures of SnS2/graphene hybrids have been designed [2/graphene, the in-situ hydrothermal process is the most common. This method can simultaneously control the structure of composite materials and the morphology and particle size of SnS2 [2/graphene composites with a high capacity of 521 mAh/g (at 0.05 A/g) by stripping the commercial SnS2 particles with graphene oxide via the hydrothermal reaction. However, the capacity was only 165 mAh/g at 2 A/g [Compositing with carbon materials is also an effective method to improve the electrochemical performance of SnS2 . Among t2 . The intfer rate ,22,23. Tdesigned . In addi of SnS2 . Howeverat 2 A/g .2 nanocrystalline anchored 3D porous graphene composite. The presence of graphene can effectively inhibit the volume expansion effect of SnS2 and improve the conductivity of the SnS2/3DG composite. The two-step reduction method significantly improves the reduction degree of graphene, resulting in an enhancement in the rate performance of the SnS2/3DG composite.In this study, to simultaneously achieve a high capacity and a high rate, we used an effective method that combines the hydrothermal and high-temperature processes to prepare a SnS4·5H2O)  and 10 mmol of anhydrous citric acid (C6H8O7)  to 80 mL of deionized water and stirred for 1 h. Another 10 mmol of thioacetamide (CH3CSNH2)  was added to the mixture after SnCl4·5H2O and C6H8O7 were completely dissolved. The mixture was stirred for an additional 30 min. Next, the well-dissolved mixture was transferred into a 100 mL hydrothermal reaction kettle and reacted at 130 °C for 12 h. After the reactor cooled to room temperature, the obtained SnS2 precipitate was centrifuged with deionized water and ethanol.We added 10 mmol of tin(IV) chloride pentahydrate  was dispersed in deionized water (the preparation concentration was 4 mg/mL) and the graphene oxide suspension was obtained after ultrasonic stripping for 1 h. Next, 20 mL of the GO suspension was added into the reaction bottle and 1 mL of SnS2 dispersion was added with a pipette gun under ultrasonic conditions. After continuous ultrasonic dispersing for 30 min, 320 mg of vitamin C (VC)  was added to the reaction bottle. The mixed solution in the reaction bottle was placed in the 80 °C water bath after the VC was dissolved evenly. The mixture hydrothermally reacted for 8 h to obtain a hydrogel with a monolith structure. The hydrogel was then freeze-dried to obtain the three-dimensional porous graphene-loaded SnS2 composite (SnS2/3DG). Finally, the SnS2/3DG was placed in a tubular furnace and thermally treated at 400 °C for 2 h in an argon atmosphere. The prepared SnSThe microstructure of the material was characterized by a Philips FEI Quanta  200F high-resolution scanning electron microscope (SEM) and transmission electron microscope (TEM). The phase analysis was carried out by a Rigaku smart-lab III X-ray diffraction (XRD), using a Cu-Kα radiation source. The proportion of each component in the composite was analyzed by a thermogravimetric (TG) analyzer . The Raman spectra of the materials were analyzed by a Horiba LabRAM HR spectrometer .2/3DG composite powder, conductive carbon black, and adhesive polyvinylidene fluoride (PVDF) were mixed with a mass ratio of 8:1:1, and a certain amount of N-methylpyrrolidone (NMP) was used as solvent to grind and prepare uniform slurry. The slurry was coated on the pretreated clean copper foil collector and dried in a vacuum oven at 100 °C for 12 h. The CR2032 button cell was assembled in the glove box, as the sodium plate was used as the counter electrode and a glass fiber  porous membrane was used as the separator. A 1 M ethylene carbonate (EC) and dimethyl monocarbonate (DMC) solvent with a volume ratio of 1:1, which was dissolved with sodium perchlorate (NaClO4), was used as the electrolyte. The cyclic voltammetry (CV) of the cell was characterized by a VMP3 . The electrochemical impedance spectroscopy (EIS) was measured on a VMP3 workstation with an amplitude of 5 mV and a frequency range of 0.01–100,000 Hz.For the electrochemical characterization, the SnS2/3DG composite was fabricated on the basis of the hydrothermal method followed by a controllable, low-temperature water bath process. As illustrated in 2 particles were obtained by mixing CH3CSNH2 and SnCl4·5H2O. The adsorbed Sn4+ ions reacted with the gradually released H2S from the decomposition of CH3CSNH2 during the hydrothermal process [2 uniformly nucleated to form nanoparticles. Next, the prepared SnS2 nanoparticles were immersed into the well-dispersed GO suspension, and a mild solvothermal method with the adding of reducing agent was introduced to not only efficiently disperse the SnS2 nanoparticles but also to reduce GO. Finally, the porous SnS2/3DG composite was successfully fabricated by the freeze-drying and thermal reduction step. This unique 3D porous structure facilitates the migration of Na+ and electrons and benefits the high sodium storage performances.The SnS process , while S2 nanocrystalline was successfully synthesized by the hydrothermal process and SnS2/3D composite was obtained by the low-temperature water bath method. 2 nanocrystalline and the SnS2/3D composite. All diffraction peaks of pure SnS2 nanocrystalline corresponds well with the standard spectrum of hexagonal SnS2 (JCPDS 23-0677) [2/3DG composite, corresponding to the typical (002) plane of graphene [2 nanocrystalline and the SnS2/3DG composite are shown in 2 nanocrystalline near 315 cm−1 reveals the vibration modes of A1g of SnS2 [−1, which belong to the D and G peaks of graphene, respectively. The prominent D peak refers to the vibration caused by the defects of graphene, while the G peak refers to the in-plane vibration of the sp2 hybridized carbon atoms of graphene [D/IG) can show the disorder degree of the carbon material. The calculated ID/IG value of the SnS2/3DG composite decreased to 1.29, which proves the high reduction degree of graphene after the thermal reduction process [SnS23-0677)  without graphene ,29. The  of SnS2 . In addigraphene . The int process .2 nanocrystalline and the SnS2/3DG composite are shown in 2 nanocrystalline with an average diameter of 20 nm was seriously agglomerated, which is not conducive to maintaining good electrochemical stability. 2/3DG composite at different magnifications where the SnS2/3DG composite displays obvious 3D porous morphology with the graphene sheets connecting to form a continuous conductive network. The complete monolith structure of the SnS2/3DG is shown in the inset of 2/3DG composite, where SnS2 nanocrystalline particles are uniformly dispersed on the graphene sheets with no obvious agglomeration because the van der Waals force between the adjacent SnS2 is destroyed by well-dispersed graphene sheets [2 nanocrystals and graphene provide a good possibility for the electrochemical performance of the SnS2/3DG composites.The morphologies of the SnSe sheets . The uni2/3DG composite, which may guarantee the cycling stability. 2 and the SnS2/3DG composite. For the pristine SnS2 sample, the mass loss in the range from room temperature to 300 °C occurred due to the evaporation of water molecules, while the mass loss over 300 to 800 °C represents the transformation from SnS2 into SnO2 [2/3DG composite also displayed a mass loss in the temperature range of 25 to 300 °C, which was due not only to the evaporation of water molecules, but also to the decomposition of residual oxygen-containing functional groups in graphene. SnS2 gradually transferred to SnO2 from 300 to 450 °C, and the excess SnS2 was further oxidized and the graphene decomposed completely at the temperature range of 450 to 800 °C. The calculated content of SnS2 was 76 wt%.In addition, the EDS mapping in nto SnO2 . The SnS2/3DG anode, 2 and the SnS2/3DG composite in the voltage range of 0.01–3.0 V. For the pure SnS2 material, the reduction peak near 1.7 V corresponds to the insertion of sodium ions into SnS2 nanocrystalline in the first discharge process of the pure SnS2 electrode (SnS2 + 4Na+ + 4e− → Sn + 2Na2S2) [2 since the second cycle, indicating the low capacity of pure SnS2. The reduction peak near 1.7 V was also found in the SnS2/3DG composite. Sn produced in the reduction provided the tin source for the Sn/Na alloying reaction at 1.2 and 0.7 V (Sn + xNa+ + xe− → NaxSn) [2/3DG composite. 2 and the SnS2/3DG composite at the current density of 100 mA/g. The SnS2/3DG composite delivered a specific initial discharge capacity and a charge specific capacity of 1276 and 557 mAh/g for the first cycle, respectively, which are much higher than those of the pure SnS2 nanocrystal electrode.To understand the sodium storage process of a SnS 2Na2S2) , while t→ NaxSn) , and the2 and the SnS2/3DG composite at the current density of 100 mA/g are shown in 2/3DG composite after 50 cycles improved to 430 mAh/g, while that of pure SnS2 was only 22 mAh/g. 2 and SnS2/3DG composites at various current densities. The SnS2/3DG composite delivered a reversible discharge specific capacity of 462 mAh/g at the current density of 100 mA/g, and the specific capacity decreased to around 407, 345, and 292 mAh/g as the current density gradually reached 200 mA/g, 500 mA/g, and 1 A/g, respectively. Even when the current density reached 2 A/g, the SnS2/3DG composite still displayed a steady discharge capacity of around 247 mAh/g, indicating an excellent rate. In addition, the reversible specific capacity of the SnS2/3DG composite returned to about 414 mAh/g when the current density was reset to 100 mA/g. However, the specific capacity of pure SnS2 was as low as 90 mAh/g at the current density of 100 mA/g, and the specific capacity of pure SnS2 almost dropped to 0 mA/g when the current density increased to 2 A/g. The specific capacity was only about 50 mAh/g when the current density returned to 100 mA/g.The cycling performance of the pure SnS2 nanocrystalline and graphene that result in the composite having a strong electrochemical rate performance and a high capacity. The reasons why SnS2/3DG has high specific capacity and excellent rate performance are as follows: (1) The high-degree reduction of 3D graphene creates the continuous conductive matrix, which is beneficial for the rate performance; (2) the porous structure of SnS2/3DG is conducive to the diffusion of electrolyte and the diffusion rate of Na+ increases; (3) the volume expansion of the SnS2 nanocrystalline is restrained by the flexible graphene sheets, and the cycling stability is improved for the solid structure of the SnS2/3DG composite. A comparison of the performance of the SnS2/3DG composite with the literature is provided in 2S2, Na14Sn5, and Sn, which is consistent with the above charge–discharge process.It is the unique three-dimensional porous structure and the interaction between the SnS2 and the SnS2/3DG composite are shown in 2 and the SnS2/3DG composite showed semicircles in the high frequency region and a diagonal line in the low frequency region, which are related to the Warburg impedance. The equivalent circuit is shown in Re represents the electrolyte impedance contributed by current collectors, electrodes, separators, and the interface between electrodes and electrolytes. Rsf and CPEsf represent the resistance and capacity of the combination of migration and the interface impedance of SEI films, respectively. Rct and CPEct represent the charge transfer impedance and charge transfer capacitance, respectively. WZ is the Warburg impedance, which is usually revealed by the straight line in the low frequency region. The SnS2/3DG composite delivered a much lower total resistance of 230.2 Ω than the pristine SnS2 (316.8 Ω), which is also lower than the hydrothermal-treated flower-like SnS2/graphene battery [w) was calculated by the EIS results, as the σw is the slope of the function of real resistance (Z’) and ω−1/2 :R is the gas constant, T is the temperature, F is the Faraday constant, n is the electron transfer number, A is the apparent electrode surface area, and C is the maximum sodium ion concentration. The obtained sodium diffusion coefficient of SnS2/3DG (1.04 × 10−14 cm2/s) is much higher than that of the SnS2 electrode (1.01 × 10−15 cm2/s). The good conductivity and fast ion diffusion coefficient improve the electrochemical performance of the SnS2/3DG composite.The Nyquist spectra of the pure SnS battery , confirmnd ω−1/2 c. The Sn2 composite was successfully prepared by combining hydrothermal and high-temperature reduction methods. The reversible capacity of the SnS2/3DG composite can reach 430 mAh/g at a current density of 100 mA/g after 50 cycles. The resistance of the SnS2/3DG composite can be effectively reduced by introducing the conductive graphene network with a high reduction degree, which is beneficial to improving its rate performance. The SnS2/3DG composite delivers an outstanding rate capability with the current density increasing from 100 mA/g to 2 A/g. This three-dimensional porous SnS2/3DG anode shows significant potential for the next-generation of SIBs.In summary, a highly conductive graphene aerogel anchored with SnS