Abstract

II–VI compound semiconductors, ZnS, ZnSe, CdS and CdSe, are well known for their important applications on a wide range of optoelectronic devices including light emitting diode and solid state laser operating in the visible spectrum range. The major difficulty of making optical devices by these materials is the fact that it cannot be easily doped to p-type. Actually the extensive efforts to make p-type materials have been continued more than thirty years. Until recently, the ZnS and ZnSe became possible to dope p-type with carrier concentration at the range of 10¹⁷–10¹⁸ cm⁻³ so that the efficient blue light laser was produced.^1,2 High quality p-type CdS and CdSe thin films still cannot be produced although there are some reports on p-type CdS:Cu amorphous-like thin films.^3,4

© 1994 Optical Society of America