SPECTROSCOPIC EVIDENCE FOR PIEZOELECTRIC EFFECTS IN WURTZITE CDS/CDSE STRAINED-LAYER SUPERLATTICES

Superlattices of wurtzite CdS/CdSe were grown on (111)A GaAs by MOCVD. Photoluminescence spectra from a range of specimens show that the structures are of type II. The dependence of emission energies and linewidths on the layer thicknesses can be accounted for by the existence of very large ( ≈ 108 V m-1) piezoelectric fields in these strained-layer systems. These fields can be partly neutralised under optical irradiation and the photoluminescence shows large excitation-dependent shifts. © 1989.