Today, we live in the age of nanomaterials with discovery of novel properties at nanometer length scales. In this thesis, we focus on perovskite oxides at such length scales in the form of thin films and heterostructures, which represent rapidly emerging class of nanomaterials significant for a rich variety of emergent phenomena. Until now, research has mostly focused on using easily accessible in-plane experimental probes to study these systems. The goal of this thesis is to expand upon this approach by establishing a solid vertical device platform and to probe the dynamics of the strongly correlated electron systems therein. As part of this goal, we focus on the fabrication of vertical hot-electron transistors based on oxide heterostructures down to the two-dimensional limit with atomic-scale precision and then the study of non-equilibrium dynamics of hot electrons across phase transitions using these device platforms. Further, we probe the spectroscopic evolution of hot-electron dynamics in oxide heterostructures using internal photoemission spectroscopy. These studies open up new avenues for probing and utilizing emergent phenomena at oxide interfaces and heterostructures using vertical device geometry.

Under certain conditions electrons in a semiconductor become much hotter than the surrounding crystal lattice. When this happens, Ohm's Law breaks down: current no longer increases linearly with voltage and may even decrease. Hot electrons have long been a challenging problem in condensed matter physics and remain important in semiconductor research. Recent advances in technology have led to semiconductors with submicron dimensions, where electrons can be confined to two (quantum well), one (quantum wire), or zero (quantum dot) dimensions. In these devices small voltages heat electrons rapidly, inducing complex nonlinear behavior; the study of hot electrons is central to their further development. This book is the only comprehensive and up-to-date coverage of hot electrons. Intended for both established researchers and graduate students, it gives a complete account of the historical development of the subject, together with current research and future trends, and covers the physics of hot electrons in bulk and low-dimensional device technology. The contributions are from leading scientists in the field and are grouped broadly into five categories: introduction and overview; hot electron-phonon interactions and ultra-fast phenomena in bulk and two-dimensional structures; hot electrons in quantum wires and dots; hot electron tunneling and transport in superlattices; and novel devices based on hot electron transport.

This volume explores the rapidly developing field of oxide thin-films and heterostructures, which exhibit unusual physical properties interesting from the fundamental point of view and for device application. The chapters discuss topics that represent some of the key innovations in the field over recent years.

Metal Oxide Semiconductors Up-to-date resource highlighting highlights emerging applications of metal oxide semiconductors in various areas and current challenges and directions in commercialization Metal Oxide Semiconductors provides a current understanding of oxide semiconductors, covering fundamentals, synthesizing methods, and applications in diodes, thin-film transistors, gas sensors, solar cells, and more. The text presents state-of-the-art information along with fundamental prerequisites for understanding and discusses the current challenges in pursuing commercialization and future directions of this field. Despite rapid advancements in the materials science and device physics of oxide semiconductors over the past decade, the understanding of science and technology in this field remains incomplete due to its relatively short research history; this book aims to bridge the gap between the rapidly advancing research progress in this field and the demand for relevant materials and devices by researchers, engineers, and students. Written by three highly qualified authors, Metal Oxide Semiconductors discusses sample topics such as: Fabrication techniques and principles, covering vacuum-based methods, including sputtering, atomic layer deposition and evaporation, and solution-based methods Fundamentals, progresses, and potentials of p–n heterojunction diodes, Schottky diodes, metal-insulator-semiconductor diodes, and self-switching diodes Applications in thin-film transistors, detailing the current progresses and challenges towards commercialization for n-type TFTs, p-type TFTs, and circuits Detailed discussions on the working mechanisms and representative devices of oxide-based gas sensors, pressure sensors, and PH sensors Applications in optoelectronics, both in solar cells and ultraviolet photodetectors, covering their parameters, materials, and performance Memory applications, including resistive random-access memory, transistor-structured memory devices, transistor-structured artificial synapse, and optical memory transistors A comprehensive monograph covering all aspects of oxide semiconductors, Metal Oxide Semiconductors is an essential resource for materials scientists, electronics engineers, semiconductor physicists, and professionals in the semiconductor and sensor industries who wish to understand all modern developments that have been made in the field.

The ability to engineer the bandstructure and the wavefunction over length scales previously inaccessible to technology using artificially structured materials and nanolithography has led to a new class of electron semiconductor devices whose operation is controlled by quantum effects. These structures not only represent exciting tools for investigating new quantum phenomena in semiconductors, but also offer exciting opportunities for applications. This book gives the first comprehensive treatment of the physics of quantum electron devices. This interdisciplinary field, at the junction between material science, physics and technology, has witnessed an explosive growth in recent years. This volume presents a detailed coverage of the physics of the underlying phenomena, and their device and circuit applications, together with fabrication and growth technology.

This book covers two broad domains: state-of-the-art research in GaN HEMT and Ga2O3 HEMT. Each technology covers materials system, band engineering, modeling and simulations, fabrication techniques, and emerging applications. The book presents basic operation principles of HEMT, types of HEMT structures, and semiconductor device physics to understand the device behavior. The book presents numerical modeling of the device and TCAD simulations for high-frequency and high-power applications. The chapters include device characteristics of HEMT including 2DEG density, Id-Vgs, Id-Vds, transconductance, linearity, and C-V. The book emphasizes the state-of-the-art fabrication techniques of HEMT and circuit design for various applications in low noise amplifier, oscillator, power electronics, and biosensor applications. The book focuses on HEMT applications to meet the ever-increasing demands of the industry, innovation in terms of materials, design, modeling, simulation, processes, and circuits. The book will be primarily helpful to undergraduate/postgraduate, researchers, and practitioners in their research.

This book systematically introduces physical characteristics and implementations of III-nitride wide bandgap semiconductor materials and electronic devices, with an emphasis on high-electron-mobility transistors (HEMTs). The properties of nitride semiconductors make the material very suitable for electronic devices used in microwave power amplification, high-voltage switches, and high-speed digital integrated circuits.