4.2. METAL NANOCLUSTERS
81
Figure 4.8. Illustration of some calculated structures of small boron nanoparticles. (F. J. Owens,
unpublished.)
4.2.4. Electronic Structure
When atoms form a lattice, the discrete energy levels of the atoms are smudged out
into energy bands. The term density of states refers to the number of energy levels in
a given interval of energy. For a metal, the top band is not totally filled. In the case of
a semiconductor the top occupied band, called the valence band, is filled, and there
is a small energy separation referred to as the band gap between it and the next
higher unfilled band. When a metal particle having bulk properties is reduced in size
to a few hundred atoms, the density of states in the conduction band, the top band
81
Figure 4.8. Illustration of some calculated structures of small boron nanoparticles. (F. J. Owens,
unpublished.)
4.2.4. Electronic Structure
When atoms form a lattice, the discrete energy levels of the atoms are smudged out
into energy bands. The term density of states refers to the number of energy levels in
a given interval of energy. For a metal, the top band is not totally filled. In the case of
a semiconductor the top occupied band, called the valence band, is filled, and there
is a small energy separation referred to as the band gap between it and the next
higher unfilled band. When a metal particle having bulk properties is reduced in size
to a few hundred atoms, the density of states in the conduction band, the top band