Overview of Nanoelectronic Devices <s> III. SOLID-STATE QUANTUM-EFFECT AND SINGLE-ELECTRON NANOELECTRONIC DEVICES <s> We propose a new negative conductance device consisting of a heterojunction bipolar transistor with a quantum well and a symmetric double barrier or a superlattice in the base region. The key difference compared to previously studied structures is that resonant tunneling is achieved by high‐energy minority carrier injection into the quantum state rather than by application of an electric field. Thus this novel geometry maintains the crucial, structural symmetry of the double barrier, allowing unity transmission at all resonance peaks and higher peak‐to‐valley ratios and currents compared to conventional resonant tunneling structures. Both tunneling and ballistic injection in the base are considered. These new functional devices have significant potential for a variety of signal processing and multiple‐valued logic applications and for the study of the physics of transport in superlattices. <s> BIB001 </s> Overview of Nanoelectronic Devices <s> III. SOLID-STATE QUANTUM-EFFECT AND SINGLE-ELECTRON NANOELECTRONIC DEVICES <s> A bipolar tunneling transistor in which ohmic contact is made to the strained p/sup +/ InGaAs quantum well of a double-barrier resonant-tunneling structure is discussed. The heterojunction transistor consists of an n-GaAs emitter and collector, undoped AlGaAs tunnel barriers, and a pseudomorphic p/sup +/ InGaAs quantum-well base. By making ohmic contact to the p-type quantum well, the hole density in the quantum-well base is used to modulate the base potential relative to the emitter and collector terminals. With control of the quantum-well potential, the tunneling current can be modulated by application of a base-to-emitter potential. The authors detail the physical and electrical characteristics of the device. It is found that the base-emitter voltages required to bias the transistor into resonance are well predicted by a self-consistent calculation of the electrostatic potential. > <s> BIB002 </s> Overview of Nanoelectronic Devices <s> III. SOLID-STATE QUANTUM-EFFECT AND SINGLE-ELECTRON NANOELECTRONIC DEVICES <s> Introduction to the Physics of Gallium Arsenide Devices (H. Grubin) Modeling of GaAs and AlGaAs/GaAs Field Effect Transistors (M. Shur) Heterostructure Field Effect Transistors (S. Pei & N. Shah) Heterojunction Bipolar Transistor Technology (P. Asbeck, et al.) Resonant Tunneling Diodes and Transistors: Physics and Circuit Applications (S. Sen, et al.) JFET Technology (W. Geideman) Design of High-Speed GaAs MESFET Digital LSI Circuits (C. Chang) GaAs FET Amplifier and MMIC Design Techniques (T. Apel) GaAs Optoelectronic Device Technology (P. Yu & P. Chen) Electro-Optical Properties of Heterojunction and Quantum Well Structures of III-V Compound Semiconductors and Their Applications in Guided-Wave Devices (W. Chang) Quantum Mechanical Corrections to Classical Transport in Submicron/Ultrasubmicron Dimensions (M. Stroscio) Index. <s> BIB003 </s> Overview of Nanoelectronic Devices <s> III. SOLID-STATE QUANTUM-EFFECT AND SINGLE-ELECTRON NANOELECTRONIC DEVICES <s> The discovery of periodic conductance oscillations as a function of charge density in very small transistors has led to a new understanding of the behavior of electrons in such small structures. It has been demonstrated that, whereas a conventional transistor turns on only once as electrons are added to it, submicronsize transistors, isolated from their leads by tunnel junctions, turn on and offagain every time an electron is added. This unusual behavior is primarily the result of the quantization of charge and the Coulomb in teraction between electrons on the small transistor. However, recent experiments demonstrate that the quantization of energy is important as well <s> BIB004 </s> Overview of Nanoelectronic Devices <s> III. SOLID-STATE QUANTUM-EFFECT AND SINGLE-ELECTRON NANOELECTRONIC DEVICES <s> We report on a novel method of fabricating 10-nm-scale GaAs dot structures using molecular beam epitaxy and in situ gas etching. Self-assembled nanometer-scale InAs dots are formed first and are used as masks for the subsequent etching of GaAs by Cl2 gas. In this approach, we also make use of HCl gas etching to remove selectively the InAs wetting layer as well as the InAs dots to yield clean and strain-free GaAs dot structures. The height and base diameter of resultant GaAs dots are studied by atomic force microscopy and found to be 10±2 nm and 30±5 nm, respectively. <s> BIB005 </s> Overview of Nanoelectronic Devices <s> III. SOLID-STATE QUANTUM-EFFECT AND SINGLE-ELECTRON NANOELECTRONIC DEVICES <s> Since first developed in the early sixties, silicon chip technology has made vast leaps forward. From a rudimentary circuit with a mere handful of transistors, the chip has evolved into a technological miracle, packing millions of bits of information on a surface no larger than a human thumbnail. And most experts predict that in the near future, we will see chips with over a billion bits. At the same time, this revolution in microelectronics has sparked a dramatic change in the way we live. An integral part of the computer industry, the microchip is found in everything from lasers, fax machines, and satellites to greeting cards and children's toys. And yet few people have any idea how chips work, or how so much information can be captured in such a miniscule space. Now, in The Quantum Dot, physicist Richard Turton provides a clear, informative look at the science that lies behind the modern revolution in microelectronics and offers an intriguing glimpse of the possible future of this rapidly evolving field. Turton illuminates the development of the microchip, in a discussion that ranges from a primer on atoms and electrons, to the properties of semiconductors (most notably, silicon), to the structure of the transistor. We learn how researchers have managed to pack the tiny silicon chip with more and more bits, and we get a state-of-the-art look at the microelectronic industry today, from the newest chip materials (such as gallium arsenide, a much faster material than silicon, used in the recently released Cray 3 supercomputer) to the exotic world of high-temperature superconductors. Perhaps most interesting, Turton offers a provocative glimpse of the future of microelectronics. Here readers enter the strange realm where quantum theory prevails and where physical events contradict our intuitive perceptions. Turton shows how researchers are leaving the transistor far behind as they struggle to exploit quantum effects to create incredibly small and fast devices, such as "designer atoms" and the quantum dot. He concludes that the range of future possibilities are immense, including devices in which electrons behave not as particles but as waves, and computers in which there are no electrical signals, only beams of light. Here then is an amazing scientific--and economic--success story, told with clarity and expertise. It will fascinate anyone curious about where modern technology is headed and what the world might look like when it gets there. <s> BIB006 </s> Overview of Nanoelectronic Devices <s> III. SOLID-STATE QUANTUM-EFFECT AND SINGLE-ELECTRON NANOELECTRONIC DEVICES <s> The study of single-electron phenomena associated with tunnelling in semiconductor nanostructures has emerged in recent years as a major forefront of condensed matter physics, whose implications range from fundamental physics to electronic device applications. This paper presents a tutorial review of the subject, with emphasis on the role of single-electron charging in such semiconductor `quantum dots'. The main purpose is to describe the various phenomena observed in these experiments and to present the theoretical understanding of these phenomena in an introductory fashion. The paper attempts to explain the underlying physics at the intuitive level and tries to draw, as much as possible, a unifying perspective on a relatively large body of knowledge acquired within a short time by the conjunction of many individual contributions. <s> BIB007 </s> Overview of Nanoelectronic Devices <s> III. SOLID-STATE QUANTUM-EFFECT AND SINGLE-ELECTRON NANOELECTRONIC DEVICES <s> We study atomiclike properties of artificial atoms by measuring Coulomb oscillations in vertical quantum dots containing a tunable number of electrons starting from zero. At zero magnetic field the energy needed to add electrons to a dot reveals a shell structure for a two-dimensional harmonic potential. As a function of magnetic field the current peaks shift in pairs, due to the filling of electrons into spin-degenerate single-particle states. When the magnetic field is sufficiently small, however, the pairing is modified, as predicted by Hund’s rule, to favor the filling of parallel spins. [S00319007(96)01418-4] <s> BIB008 </s> Overview of Nanoelectronic Devices <s> III. SOLID-STATE QUANTUM-EFFECT AND SINGLE-ELECTRON NANOELECTRONIC DEVICES <s> We found a new self-organizing growth mode in the metalorganic vapor-phase epitaxy (MOVPE) on high-index GaAs (311)B substrates to form well-ordered arrays of quantum-dots. The spontaneous interaction of strained InGaAs layers with AlGaAs buffer layers results in high-density rows of disk-shaped InGaAs quantum dots buried within AlGaAs microcrystals due to lateral mass transport. The size and distance of the disks are controlled independently in the mesoscopic size range by the In composition and the InGaAs layer thickness, respectively, without affecting the uniformity and the shape. The photoluminescence spectra exhibit narrow linewidth and high efficiency at room temperature. Buried quantum disk structures are formed also on other GaAs (n11)B substrates and on InP (311)B substrates, indicating this growth mode to be universal in the strained layer growth on high-index semiconductor surfaces. <s> BIB009 </s> Overview of Nanoelectronic Devices <s> III. SOLID-STATE QUANTUM-EFFECT AND SINGLE-ELECTRON NANOELECTRONIC DEVICES <s> The basic principles of single-electron charging effects are explained. The fabrication of island and tunnel junction structures in which single-electron devices can be realised is described. Structures based on metals, GaAs/AlGaAs heterointerfaces, @d-doped GaAs, silicon and silicon-on-insulator have been considered and some of the applications of single electronics such as the current standard and the single electron memory are described in this review. <s> BIB010 </s> Overview of Nanoelectronic Devices <s> III. SOLID-STATE QUANTUM-EFFECT AND SINGLE-ELECTRON NANOELECTRONIC DEVICES <s> Waves and particles. The Schrodinger equation. Tunnelling. The harmonic oscillator. Basis functions, operators, and quantum dynamics. Stationary perturbation theory. Time-dependent perturbation theory. Motion in centrally symmetric potentials. Electrons and anti-symmetry. Solutions to selected problems Index. <s> BIB011
A number of nanometer-scale solid-state replacements for the bulk-effect semiconductor transistor have been suggested to overcome the difficulties discussed above. All of these devices function by taking advantage of effects that occur on the nanometer-scale due to quantum mechanics BIB011 , [130] ,  ,  ,  . The essential structural feature that all of these devices have in common is a small "island" composed of semiconductor or metal in which electrons may be confined. This island of a nanoelectronic device assumes a role analogous to that of the channel in an FET. As is explained in greater detail below, the extent of confinement of the electrons in the island defines three basic categories of solid-state nanoelectronic devices. • Quantum Dots (QD's or "artificial atoms") BIB006 , BIB007 ,  ,  ,  ,  ,  , BIB008 , BIB005 , BIB009 . Island confines electrons with zero classical degrees of freedom remaining. • Resonant Tunneling Devices (RTD's)  , BIB006 , BIB001 ,  , BIB002 . Island confines electrons with one or two classical degrees of freedom. • Single-Electron Transistors (SET's) BIB004 ,  , BIB010 ,  . Island confines electrons with three classical degrees of freedom. The composition, shape, and size of the island gives the different types of solid-state nanoelectronic devices their distinct properties. Controlling these factors permits the designer of the device to employ quantum effects in different ways to control the passage of electrons on to and off of the island. For example, the mean free path of mobile electrons can be much greater in semiconductors than in metals. Thus a mobile electron might travel coherently all the way across a semiconductor island, without severe collisions. This means that conductivity of a device can be strongly enhanced or suppressed by quantum mechanical interference between separate paths an electron might take through the device. As is well known, microelectronic devices are made primarily from silicon (Si), an element in group IV of the periodic table. Presently, however, most solid-state nanoelectronic devices incorporate semiconductors made from combinations of elements from groups III and V of the periodic table-e.g., gallium arsenide (GaAs) and aluminum arsenide (AlAs) BIB003 ,  . The mobilities of electrons are higher in these III-V semiconductors  , and it is also easier to fabricate defect-free junctions between different III-V semiconductors than it is for junctions between two group IV semiconductors, such as Si and Ge.