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A compound semiconductor is a semiconductor compound composed of chemical elements of at least two different species. These semiconductors form for example in periodic table groups 13–15 (old groups III–V), for example of elements from the Boron group (old group III, boron, aluminium, gallium, indium) and from group 15 (old group V, nitrogen, phosphorus, arsenic, antimony, bismuth).
Precious metals such as gold, silver, and platinum have been used for millennia to create objects of cultural and artistic significance. In jewelry, they are a cornerstone for crafting wedding bands , engagement rings , and ceremonial adornments , often symbolizing love, commitment, and social status.
Non-metallic and semiconductor materials prepared in bulk form may also be referred to as ingots, particularly when cast by mold based methods. [2] Precious metal ingots can be used as currency (with or without being processed into other shapes), or as a currency reserve, as with gold bars .
Precious metals were historically used as coinage, but in the modern era, coinage metals have extended to at least 23 of the chemical elements. [8] There is also extensive use of multi-element metals such as titanium nitride [9] or degenerate semiconductors in the semiconductor industry.
Wafers of single-crystal sapphire are also used in the semiconductor industry as substrates for the growth of devices based on gallium nitride (GaN). The use of sapphire significantly reduces the cost, because it has about one-seventh the cost of germanium. Gallium nitride on sapphire is commonly used in blue light-emitting diodes (LEDs). [68]
The platinum-group metals (PGMs), also known as the platinoids, platinides, platidises, platinum group, platinum metals, platinum family or platinum-group elements (PGEs), are six noble, precious metallic elements clustered together in the periodic table. These elements are all transition metals in the d-block (groups 8, 9, and 10, periods 5 ...
The table below shows some of the parameters of common superconductors.X:Y means material X doped with element Y, T C is the highest reported transition temperature in kelvins and H C is a critical magnetic field in tesla.
A 1 cm 3 specimen of a metal or semiconductor has the order of 10 22 atoms. [29] In a metal, every atom donates at least one free electron for conduction, thus 1 cm 3 of metal contains on the order of 10 22 free electrons, [ 30 ] whereas a 1 cm 3 sample of pure germanium at 20 °C contains about 4.2 × 10 22 atoms, but only 2.5 × 10 13 free ...