Theory of Transport in Semiconductor Devices
Abstract
ONR Abstract Theory of Transport in Semiconductor Devices A. Dyson and B. K. Ridley Semiconductor devices form the core of modern electronic systems that are continually evolving. The need for faster, more versatile, devices has led to brilliantly-engineered structures, so small that some dimensions can be measured in number of atoms. In such structures quantum effects become important. Our ONR project is a study of the electronic properties of such devices, now commonly referred to as nanostructures (a nanometer being a billionth part of a metre). Semiconductors are crystals, but they are not superconductors. In them, the flow of electrons is continually impeded by defects in the crystal lattice, which the art of crystal growing can reduce but never eliminate. A much more fundamental impediment are the vibrations of the crystal lattice. These exist at all practicable temperatures and cannot be eliminated. Quantum theory describes them in terms of particle-like entities known as phonons. Our main concern is to describe the electron-phonon interaction, how this is modified by the confinement of both electrons and phonons, that is a result of nanometer dimensions, and how it depends on the power of the device and the number of electrons involved. Results here have direct application to the modern, high-power, field-effect transistor. In addition, we speculate on the possibility of more esoteric devices that are capable of generating terahertz radiation, the sort that can be used, for example, in airport security. A word on methods. We generate theoretical models that are analytic and as simple as possible in order obtain an intuitive understanding of what is going on. These, inevitably, given the complexity of the topic, can only be approximate. In tandem, we have developed powerful numerical techniques (so-called Monte Carlo models) that follow in detail the flow of both electrons and phonons in time, which give, in principle, a much more accurate account. We believe this combination of analytic and Monte Carlo techniques is ideal for our project.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512193
Entities
People
- Angela Dyson
Organizations
- Office of Naval Research
- United States Navy
- University of Hull