Quasi-conductor are the divided class of substances. People got known about these substances in the end of the 19th century, but only in the 20th century scientists managed to obtain more knowledge about them. The first successful research was carried out by the Russian scientists in 1923. They proved that semiconductors may be utilized to accelerate fluctuations. But such devices as igbt modules that are used nowadays were created considerably later. Only in the beginning of the 50's with the invention of transistors in 1949 the broad use of crystal detectors started. Since then a lot of persons all over the world become interested in such type of substance as semiconductors.

Induced emission is actually a quite interesting feature of semiconductors that has been researched for several tens of years. First laser system was developed with utilizing of semiconductors. The first variant was based on p - n barriers, the latest ones - on heterojunction.

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