GROWTH AND CHARACTERIZATION OF P-TYPE VPE ZNS LAYERS

The conductivity type control of ZnS was demonstrated for the open tube VPE growth on GaAs substrates from a ZnS powder source. The p-type character of the layer grown under the simultaneous addition of a few at% excess Zn and a large amount of NH3 in the growth system was revealed mainly by the sign of the Seebeck effect and electron-beam induced current profile measurements at the cleaved faces of the epitaxial layers. Various kinds of changes corresponding to the change of the conduction type were observed in the photoluminescence spectra of the edge and bound exciton emissions, and trap levels examined by the transient thermoluminescence method. The role and meaning of the simultaneous addition of Zn and NH3 are discussed together with the observed change of the amounts of Ga and As impurities from the substrate by EPMA. © 1989.