Crystalline semiconductors such as silicon can catch photons
and convert their energy into electron flows. New research shows that a little
stretching could give one of silicon's lesser-known cousins its own place in
the sun.
(June 25, 2015) Nature
loves crystals. Salt, snowflakes and quartz are three examples of crystals –
materials characterized by the lattice-like arrangement of their atoms and
molecules.
Industry loves crystals, too. Electronics are based on a
special family of crystals known as semiconductors, most famously silicon.
To make semiconductors useful, engineers must tweak their
crystalline lattice in subtle ways to start and stop the flow of electrons.
Semiconductor engineers must know precisely how much energy
it takes to move electrons in a crystal lattice.
This energy measure is the band gap. Semiconductor materials
such as silicon, gallium arsenide and germanium each have a band gap unique to
their crystalline lattice. This energy measure helps determine which material is
best for which electronic task.