DEEP BLUE AND UV PHOTOLUMINESCENCE FROM ZNS/CDS SUPERLATTICES AND QUANTUM-WELLS

Ultrathin quantum wells (QWs) and short period superlattices (SLs) of ZnS/CdS were grown on (001) GaAs substrates by molecular beam epitaxy using elemental sources. The relaxation of the ZnS buffer and pseudomorphic growth of CdS QWs was investigated by reflection high-energy electron diffraction. The QW structures with 1 to 4 monolayers emit photoluminescence in the ultraviolet spectral region even at room temperature, whereas the SLs emit in the blue range. The SL structures were ascertained by the observation of satellites in X-ray diffraction spectra.