Contents
Introduction. 1 .l. Historical survey germanium and tellurium and compounds such as silicon carbide, arsenides, phosphides and antimonides, some of the IIb-VIb compounds like zinc and cadmium sulphides, selenides and tellurides, and finally lead sulphide, selenide and telluride and lead-tin tellurides. In a final section some comments are made on recombination radiation in semiconducting lasers and on the problems of utilizing the high-band-gap visible emitters as carrier-injection sources of radiation.