NANOTECHNOLOGY—TECHNOLOGY ON A MOLECULAR SCALE - Chemistry: Notable Research and Discoveries - page 56

Electrons can emit light when they fall from a higher energy level to
a lower one. A light-emitting diode (LED) is a semiconductor in which
the electrons emit light of a certain wavelength (color). Bulky materi-
als tend to emit light of a fi xed wavelength that depends on the aver-
age energy levels, but in quantum dots, the discrete energy levels can
be changed by the addition or subtraction of just a few electrons—in
the crowded conditions of a bulky material, one electron more or less
would not be noticed, but this is not true in quantum dots. By varying
the size, researchers can easily make quantum dot LEDs emit a variety
of wavelengths.
nationalnanotechnologyInitiative
Sorting out priorities among the many branches of science
and technology that are competing for attention and fund-
ing is not an easy task. The United States established the
National Science and Technology Council (NSTC) in 1993 to
advise the president on goals and strategic pursuits in the
various fi elds. Soon thereafter, the potential and promise of
nanotechnology brought attention to this fi eld of research,
and in the 2001 federal budget, nanoscale science and tech-
nology came into the spotlight when it was identifi ed as being
an initiative—the National Nanotechnology Initiative—which
means the government is fi rmly committed to funding this
research. The Nanoscale Science, Engineering and Technol-
ogy Subcommittee, a component of NSTC, was established
to guide policy and make recommendations.
One of the most important jobs of the National Nanotech-
nology Initiative is to coordinate the efforts of the large num-
ber of government agencies that fund scientifi c and techno-
logical research. Nanotechnology involves not just chemistry
but also physics, biology, engineering, materials science, and
other disciplines, so collaboration is critical. Twenty-six fed-
eral agencies participate in the initiative, 13 of them with
signifi cant research budgets. In 2007, for example, these 13