Effect of p-type transition metal dichalcogenide molybdenum ditelluride (p-MoTe2) layer formation in Cadmium Telluride solar cells from numerical analysis
In this paper, we have investigated the effects of transition metal dichalcogenide namely Molybdenum ditelluride (MoTe2) layer formation in between Cadmium Telluride (CdTe) absorber layer and Mo back contact from numerical modeling. The main purpose was to investigate the possible effects of p-type MoTe2 in CdTe thin film solar cell. Energy band line-up in the vicinity of Mo/MoTe2/CdTe interface is investigated to explain the interface properties in terms of various parameters. It was found that p-type MoTe2 has some effects to the performance of CdTe thin film solar cells. Thickness, bandgap energy and carrier concentration of p-MoTe2 all have been varied in the numerical simulation to observe its effects on the cell performance. It was found that when thickness of MoTe2 is less than 20 nm, the cell efficiency decreases, which may be due to the shunting caused by the thinner p-MoTe2. Furthermore, the increase in MoTe2 bandgap results in unfavorable effect to the performance of the cell mainly due to the possibility of electrons to drift towards the back contact and recombination. The increase of the carrier concentration improves the cell performance. This could be attributed to the less recombination of electrons as well as less built in potential (Vbi) at MoTe2/CdTe junction.
Asymmetric electrode incorporated 2D GeSe for self-biased and efficient photodetection
2D layered germanium selenide (GeSe) with p -type conductivity is incorporated with asymmetric contact electrode of chromium/Gold (Cr/Au) and Palladium/Gold (Pd/Au) to design a self-biased, high speed and an efficient photodetector. The photoresponse under photovoltaic effect is investigated for the wavelengths of light (i.e. ~220, ~530 and ~850 nm). The device exhibited promising figures of merit required for efficient photodetection, specifically the Schottky barrier diode is highly sensitive to NIR light irradiation at zero voltage with good reproducibility, which is promising for the emergency application of fire detection and night vision. The high responsivity, detectivity, normalized photocurrent to dark current ratio (NPDR), noise equivalent power (NEP) and response time for illumination of light (~850 nm) are calculated to be 280 mA/W, 4.1 × 10 9 Jones, 3 × 10 7 W −1 , 9.1 × 10 −12 WHz −1/2 and 69 ms respectively. The obtained results suggested that p-GeSe is a novel candidate for SBD optoelectronics-based technologies.
Adaptation of thin-film photovoltaic technology for use in space
The anticipated deployment of large numbers of satellites in low Earth orbit (LEO) for global telecommunications networks renews interest in producing solar power systems that are lightweight, robust, resistant to radiation damage and relatively inexpensive. Promising near term thin-film candidates are amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). The authors discuss the modifications that are necessary to adapt terrestrial thin-film technology for use in space. They characterize expected module performance and present results of tests performed on sample cells. They consider the possibility of achieving aggressive cost, weight and performance targets through the use of thin-film photovoltaic (PV) technology.