THE PECULIARITIES OF THE PHYSICS OF WIDE BAND-GAP SEMICONDUCTORS AND THEIR APPLICATIONS

One usually regards the semiconductors, for which the bandgap exceeds approximately 2 eV, as the ''wide bandgap'' family. These materials ha ve different nature of chemical bonds and crystal structure. However, electronic and optical phenomena inside the family exhibit several sim ilar qualities. Among the wide bandgap semiconductor family: diamond, silicon carbide SiC, gallium phosphide GaP, cadmium sulfide CdS and it s relatives in the 11 VI group seem to have a special place. With the progress of optoelectronics and other fields of practical applications , in particular high-temperature devices and detectors of high energy photons and charged particles, the interest towards wide bandgap semic onductors increases. In the present review, taking as an example a lim ited number of the better understood substances from the family of the wide bandgap semiconductors, the author discusses typical features of the electronic processes and structural changes initiated, first of a ll, by a high level of excitation of their electronic ''subsystem'', a nd by the existence of the centers of carriers' localization with deep energy levels.