Photographic Lenses (wide-angle)
Germanium is extensively used in metallurgy and in the production of solid state electronics. Added to beryllium, it leads to increasing ductility, and added to copper, it improves chemical resistivity. It is also used in several brazing alloys. Germanium in the form of (GeO2) is an important constituent of industrial glasses because of its infrared transmission and high refractive index.
Germanium has played by far the most important role in the development of solid state electronics beginning with the discovery of the transistor in 1948. It is one of the most studied and best understood of all elements.
The discovery of the transistor action pointed the way to numerous solid state electronics phenomena which formed the basis of a new science and technology of solid state electronics. It was with germanium that almost perfect single crystals never achieved with other elements were developed. Cyclotron resonance, a means for determining the effective mass of charge carriers, was first observed in germanium single crystals. A variety of optical and magneto-optical measurements allowed for determining of fundamental parameters necessary for understanding the band structure of solids.
Nowadays germanium is used in the production of electronic components such as diodes, transistors, light and temperature sensors, etc.