Plasma-Assisted MOCVD Growth of GaAs/GaN/GaAs Thin-Layer Structures by N-As Replacement Using N-Radicals

Abstract

GaAs/GaN/GaAs thin-layer structures were grown by plasma-assisted low-pressure metalorganic chemical vapor deposition. GaN layers were formed by exposing the surfaces of GaAs epitaxial layers to nitrogen-radical fluxes. When the nitrogen amount exceeded that in one-monolayer-thick GaN, the GaN/GaAs interfaces deteriorated drastically. Low-temperature photoluminescence from the structures suggests that the two-dimensional growth of GaN is limited to one-monolayer thick and that the excess nitrogen atoms form GaN clusters in the underlying layers. The one-monolayer-thick GaN embedded in GaAs shows intense photoluminescence, whereas the GaN cluster is non-radiative, probably because of the defects caused by the large lattice-mismatch between GaN and GaAs.