Purge Effect on Heterointerfaces of ZnSe/MgS Superlattices Grown by Metalorganic Vapor Phase Epitaxy

Heterointerface properties of ZnSe/MgS superlattices (SLs) grown by -0.52pt metalorganic vapor phase epitaxy (MOVPE) are characterized using X-ray diffraction measurements and in situ monitoring of optical multiple reflection in the SL films. These studies showed the formation of MgSe-related extra interface layers in the SLs. It was found that a purge with a Zn precursor effectively suppresses the extra interface layer formation. By a purge with a Zn precursor, linewidths of the photoluminescence (PL) spectra became much narrower than those of SLs grown without purging. Monolayer exciton PL peaks were clearly observed in a SL with narrow wells. This demonstrates that a purge with a Zn precursor effectively improves the abruptness and the atomic flatness of the ZnSe/MgS heterointerfaces.