NANOSCALE DEVICES: APPLICATIONS AND MODELING - Bio-Inspired and Nanoscale Integrated Computing - page 31

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NANOSCALE DEVICES:
APPLICATIONS AND MODELING
Alireza Nojeh
This chapter starts with a discussion of the roots of nanotechnology, the
distinguishing aspects of the nanoscale, and the definition of nanoscale devices.
Some of the common materials and techniques used to fabricate such devices are
briefly reviewed. The physics of the operation of nanoscale devices is the subject of
the next part. Quantum dots, resonant tunneling diodes, and single-electron
transistors, which can be made using traditional fabrication methods, are first
studied. Then a number of devices based on newer materials such as carbon
nanotubes are introduced, and how the properties of these materials provide
opportunities for innovative device design is discussed. The last part of the chapter
deals with the theoretical study, modeling, and simulation of nanoscale devices.
The challenge of the many-body problem and the difference between first-
principles and semi-empirical approaches are highlighted. A brief introduction
to some of the simulation methods, such as the Hartree-Fock approximation,
density functional theory, molecular dynamics, tight-binding, and Monte Carlo,
concludes the chapter.
2.1. INTRODUCTION
2.1.1. The Roots of Nanotechnology
Although one can easily think of many milestones, such as the invention of the
scanning tunneling and atomic force microscopes or the discovery of fullerenes in
the 1980s, that have pushed us more and more into the nano era, it is not easy to
define a single point in time when it all started. For instance, many of the imaging
tools relevant to the nanoscale, such as electron microscopes, have been around