NANOSCALE DEVICES: APPLICATIONS AND MODELING - Bio-Inspired and Nanoscale Integrated Computing - page 32

for a long time. But as we see, they have been called microscopes and not
nanoscopes. One tends to think that at least one aspect of what we consider
nanotechnology is the extension of microtechnology to smaller sizes, and it is hard
to separate the roots of these two, although some clear distinctions can be drawn
between them. As discussed in Chapter 1, a particularly interesting early reference
to small scale devices and technologies was made by physicist Richard Feynman in
a lecture he gave in 1959 [1]. Feynman did not make specific claims about what
would happen in future, but rather gave a tour of what could very logically
and naturally be available at small scales from a purely scientific point of view
(i.e., without contradicting the laws of physics as we know them). After almost
half a century, that lecture can be an insightful introduction for newcomers to the
field of nanotechnology and a great inspiration to seasoned nanotechnologists.
2.1.2. Two Ways to Reach the Nanoscale
It could be argued that one of the most dramatic changes in our lifestyles has been
brought about by the rapid advance of the microelectronics industry over the last
few decades. The steady decrease in the size of transistors, the fundamental building
blocks of microelectronic circuits, has lead to today's low cost and high perfor-
mance computer chips. For instance, the transistors in your computer are about a
tenth of a micrometer in size, or maybe even about a twentieth of a micrometer if
you have recently bought a new one—that is about 50 nanometers (nm). Thus, for
those who work in this industry, nanoelectronics is a completely natural continua-
tion of microelectronics. In fact, many tend to define a device as being a nanodevice
if one of its dimensions is smaller than 100 nm. In that sense, the semiconductor
industry has already entered the era of nanoelectronics—without really calling itself
nanotechnology!
Pushing our traditional microfabrication techniques to make devices much
smaller than a micrometer is one way of approaching the nanoscale. One could
think of this as the art of ''carving'' ultra-small objects. However, there are objects
that are very small by their nature, such as molecules. They provide another
approach to nanotechnology: use small objects already available to us through
nature and try to add some level of control to where and how they are arranged so
that they can perform the functions we are interested in.
2.1.3. The ''Nano'' Difference
As pointed out in Chapter 1, there is more to the nanoscale than just the ability to
pack a large number of devices in a small area or to manipulate very small objects.
There is a fundamental reason that makes ''nano'' attractive from a scientist's
point of view but a nonexpert might have a little more difficulty appreciating it.
Let us see what that is.
We know that objects are made of individual units called atoms that are
extremely small. This topic you are reading, for example, contains on the order of
one hundred trillion trillion atoms—that is a 1 with 26 zeros in front of it! When