PHOTOLUMINESCENCE PROPERTIES OF ZNS EPILAYERS GROWN BY METALORGANIC MOLECULAR-BEAM EPITAXY

A comprehensive study is reported of the epitaxial growth and photolum inescence properties of ZnS on GaAs and Si. Conventional and photoassi sted MOMBE and CBE growth using H2S, DipS and t-BuSH, with DeZn showed higher growth rates in the presence of H, or under photoassisted cond itions. At low temperatures, the radical alkyl by-products from the cr acked precursors were identified as reducing the growth rate through s urface site blocking. A CaF2 buffer layer was shown to improve the cry stalline quality due to elimination of a reaction between S and Si. Lo w temperature photoluminescence studies identified recombinations from the ground and the first excited states of the free exciton as well a s from neutral donor and acceptor bound excitons, and phonon replicas.