Germanium is a hard, brittle metalloid that was first used about
a half century ago as a semiconductor material in radar units
and as the material for the first transistors. Today, it is used
as a polymerization catalyst for polyethylene terephthalate
(PET), a commercially important plastic; as a component of glass
in telecommunications fiber optics; as a lens or window in
infrared night-vision devices; and as a semiconductor and
substrate in electronic circuitry and solar cells.Because of its
small band gap, it reponds efficiently to infrared light and is
used in infrared spectroscopes for thermal imaging devices.
Germanium oxide has an index of refraction that makes it useful
in wide-angle lenses. IBM uses germanium for the avalanche
photodetectors in their zEnterprise 196 microprocessor systems.
Domestic Production and Use: The major end uses for germanium,
worldwide, were estimated to be fiber-optic systems, 30%;
infrared optics, 25%; polymerization catalysts, 25%; electronics
and solar electric applicati