5.
Benjamin Fulford, "Chipmakers Are Running Out of Room: The Answer Might Lie in 3-D," Forbes.com, July
22, 2002, http://www.forbes.com/forbes/2002/0722/173_print.html.
6.
NTT news release, "Three-Dimensional Nanofabrication Using Electron Beam Lithography," February 2,
2004, http://www.ntt.co.jp/news/news04e/0402/040202.html.
7.
László Forró and Christian Schonenberger, "Carbon Nanotubes, Materials for the Future,"
Europhysics News
32.3 (200l), http://www.europhysicsnews.com/full/09/article3/article3.html. Also see
http://www.research.ibm.com/nanoscience/nanotubes.html for an overview of nanotubes.
8.
Michael Bernstein, American Chemical Society news release, "High-Speed Nanotube Transistors Could Lead
to Better Cell Phones, Faster Computers," April 27, 2004, http://www.eurekalert.org/pub_releases/2004-
04/acs-nt042704. php.
9.
I estimate a nanotube-based transistor and supporting circuitry and connections require approximately a ten-
nanometer cube (the transistor itself will be a fraction of this), or 10
3
cubic nanometers. This is conservative,
since single-walled nanotubes are only one nanometer in diameter. One inch = 2.54 centimeters = 2.54
°
10
7
nanometers. Thus, a 1-inch cube = 2.54
3
°
10
21
= 1.6
°
10
22
cubic nanometers. So a one-inch cube could
provide 1.6
°
10
19
transistors. With each computer requiring approximately 10
7
transistors (which is a much
more complex apparatus than that comprising the calculations in a human interneuronal connection), we can
support about 10
12
(one trillion) parallel computers.
A nanotube transistor-based computer at 10
12
calculations per second (based on Burke's estimate) gives us
a speed estimate of 10
24
cps for the one-inch cube of nanotube circuitry. Also see Bernstein, "High-Speed
Nanotube Transistors."
With an estimate of 10
16
cps for functional emulation of the human brain (see discussion later in this
chapter), this gives us about 100 million (10
8
) humanbrain equivalents. If we use the more conservative 10
19
cps estimate needed for neuromorphic simulation (simulating every nonlinearity in every neural component;
see subsequent discussion in this chapter), a one-inch cube of nanotube circuitry would provide only one
hundred thousand human-brain equivalents.
10.
"Only four years ago did we measure for the first time any electronic transport through a nanotube. Now, we
are exploring what can be done and what cannot in terms of single-molecule devices. The next step will be to
think about how to combine these elements into complex circuits," says one of the authors, Cees Dekker, of
Henk W. Ch. Postma et al., "Carbon Nanotube Single-Electron Transistors at Room Temperature,"
Science
293.5527 (July 6, 2001): 76–129, described in the American Association for the Advancement of Science
news release, "Nano-transistor Switches with Just One Electron May Be Ideal for Molecular Computers,
Science
Study Shows," http://www.eurekalert.org/pub_releases/2001-07/aaft-nsw062901.php.
11.
The IBM researchers solved a problem in nanotube fabrication. When carbon soot is heated to create the tubes,
a large number of unusable metallic tubes are created along with the semiconductor tubes suitable for
transistors. The team included both types of nanotubes in a circuit and then used electrical pulses to shatter the
undesirable ones-a far more efficient approach than cherry-picking the desirable tubes with an atomic-force
microscope. Mark K. Anderson, "Mega Steps Toward the Nanochip,"
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