INTERFACE CONTROL IN GAAS/GAINP SUPERLATTICES GROWN BY OMCVD

In this paper, we show that the deleterious effect of the reaction of arsine with the underlying GaInP, when growing GaAs on GaInP, can be overcome by the growth of a thin (approximately 0.8 nm) GaP interfacial layer. In addition, we show the usefulness of X-ray rocking curve simulations in aiding the understanding and thereby control of heterointerfaces. Variable low temperature photoluminescence measurements were used to confirm the existence of a low bandgap interfacial layer at the GaInP to GaAs interface, predicted from X-ray simulations, by comparing the energy separation between heavy and light-hole emissions in samples with and without such interfacial layers. The X-ray simulations and photoluminescence measurements also indicated an In contamination of the GaAs quantum well. The source of the In contamination was shown to be the susceptor, which is coated with In based compounds. Both In and As contamination can be a problem in reactors where the carrier gas flows over the susceptor before arriving at the substrate.