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Abstract:-
Nanotechnology and Electronics,
the article focuses on the present state of micro-electronics and the problems
faced at nano levels in silicon nanotechnology (smaller than 100nm) and the
options and solutions available by Nanotechnology. Also about the application
of new nano technological solutions available like the use of nanotubes,
nanowires, nanodots and other nanomaterials in electronics and the physics
governing their behavior at nanoscale.
Keywords:-
Nanotechnology, nanoelectronics, carbon nanotube,
semiconductor nanotechnology, CMOS nanotechnology, Silicon nanotechnology,
nanowires, nanoparticles, nanodevices, nanophysics.
1.
INTRODUCTION:-
Nanotechnology
has affected nearly every field of Engineering and Science but most of the
innovation and funding (private) in Nanotechnology came from Electronics
giants, in search for making faster computers. The other fields that worked
with nano electronics hand in hand were nano-photonics and
nano-instrumentation. Also the marketing and making of nano gadgets started
from the computers and mobiles which are the only machines made at nano scale
that were available economically in the market at a very early stage. So it is
of no doubt that the only area where nanotechnology penetrated deeply is
electronics where it had lead to cost advantage and performance attributes
especially in transistors and today we have 1 billion transistors in the latest
processor. The backbone of nanotechnology in electronics are the results that
we have taken from nano physics that is quantum physics and solid state physics
because then we talk of things at nano scale these are the two stream of
physics that helps us in predicting things. Eventually when we talk of
electronics it is all about electrons and how we use them in various gadgets to
get the required result. So it is very important to know electrons and how it
behaves at nano scale in electronics.
Introduction
and Importance Quantum Mechanics:-
A
fundamental aspect of quantum mechanics is the particle-wave duality,
introduced by De Broglie, according to which any particle can be associated
with a matter wave whose wavelength is inversely proportional to the particles
linear momentum. Whenever the size of a physical system becomes comparable to
the wavelength of the particles that interact with such a system, the behavior
of the particles is best described by the rules of quantum mechanics. All the
information we need about the particle is obtained by solving its Schrodinger
equation. The solutions of this equation represent the possible physical states
in which the system can be found. But quantum mechanics is not required to
describe the movement of objects in the macroscopic world. The wavelength
associated with a macroscopic object is in fact much smaller than the objects
size, and therefore the trajectory of such an object can be excellently derived
using the principles of classical mechanics. Things change, for instance, in
the case of electrons orbiting around a nucleus, since their associated
wavelength is of the same order of magnitude as the electron-nucleus distance.
We can use
the concept of particle-wave duality to give a simple explanation of the
behavior of carriers in a semiconductor nanocrystal. In a bulk inorganic
semiconductor, conduction band electrons (and valence band holes) are free to
move throughout the crystal, and their motion can be described satisfactorily
by a linear combination of plane waves whose wavelength is generally of the
order of nano-meters. This means that, whenever the size of a semiconductor
solid becomes comparable to these wavelengths, a free carrier confined in this
structure will behave as a particle in a potential box. The solutions of the
Schrodinger equation in such case are standing waves confined in the potential
well, and the energies associated with two distinct wave functions are, in
general, different and discontinuous. This means that the particle energies
cannot take on any arbitrary value, and the system exhibits a discrete energy
level spectrum. Transitions between any two levels are seen as discrete peaks
in the optical spectra, for instance. The system is then also referred to as
quantum confined.
The main
point here is that in order to rationalize (or predict) the physical
properties
of nanoscale materials, such as their electrical and thermal conductivity or
their absorption and emission spectra, we need first to determine their energy
level structure.
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