Chemical reaction at the ZnSe/GaAs interface detected by Raman spectroscopy

When ZnSe is deposited at temperatures commonly used for epitaxy onto GaAs, the possibility arises that selenium or zinc reacts with the substrate and thin interfacial layers consisting of a gallium selenide or a zinc arsenide are formed. In particular, Ga2Se3, which is thermodynamically the most stable, has been suggested as a likely candidate. In this study we present evidence for the formation of Ga2Se3 using Raman spectroscopy as a fingerprint technique. Ga2Se3 layers were grown on GaAs and the Raman spectra thereof were compared with those of ZnSe/GaAs heterostructures.