Tellurium Tellurium Tellurium is a chemical element with symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur. It is occasionally found in native form as elemental crystals. Tellurium is far more common in the universe as a whole than on Earth. Its extreme rarity in the Earth's crust, comparable to that of platinum, is due partly to its high atomic number, but also to its formation of a volatile hydride which caused it to be lost to space as a gas during the hot nebular formation of
Germanium made with low-cost, well-established production techniques of the silicon chip industry. Solar panels are a major use of germanium. Germanium is the substrate of the wafers for high-efficiency multijunction photovoltaic cells for space applications. High-brightness LEDs, used for automobile headlights and to backlight LCD screens, are an important application. Because germanium and gallium arsenide have very similar lattice constants, germanium substrates can be used to make gallium arsenide solar cells. The Mars Exploration Rovers and several satellites use triple junction gallium arsenide on germanium cells. Germanium-on-insulator substrates are seen as a potential replacement for silicon on miniaturized chips. Other uses