Ga2Te3 and tellurium interfacial layers in ZnTe/GaSb heterostructures studied by Raman scattering

Abstract

Raman spectroscopy of ZnTe layers grown by molecular beam epitaxy on (100) GaSb is reported. When the laser excitation is above the band gap of the ZnTe, scattering is observed only from the ZnTe LO mode and overtones. With excitation below the ZnTe band gap, a series of low frequency peaks is observed. By comparison with bulk data these peaks are identified as originating from Ga2Te3 and Te present at the GaSb/ZnTe interface. We conclude that the presence of this interface material may degrade the layer quality and give rise to the anomalously large strain previously reported for such epilayers.