Quasi-conductor are the divided class of matters. Such class was researched in early 1980's but there were no needed technologies to perform the further experiments. The analysis of semiconductors was carried on only in the 1920's. In 1923 Russian physicists proved the ability of utilizing of semiconductor-metal contacts to quicken the generation of fluctuations. But such parts as igct which are used nowadays were invented significantly later. Only in the beginning of the 50's with the invention of transistors in 1949 the broad usage of crystal detectors started. Since then a lot of persons all over the world become interested in such type of substance as semiconductors.
A lot of physicists perform a great deal of experiments simply to gain more knowledge about such characteristic of semiconductors as stimulated radiation. It caused the appearing of semiconductor laser system based on usage of p - n barriers and then on heterojunction.