Wide gap II-VI superlattices of ZnSe-Zn1−xMnxSe

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Abstract
In this letter we report the first growth of wide gap II‐VI semiconductor superlattices of Zn1−xMnxSe (0<x1−xMnxSe (0<xx=0.3; above this mole fraction a predominance of the hexagonal phase is observed. For the superlattices and epilayers reported here, only the zincblende phase (100) is present over the entire composition range investigated. Transmission electron microscopy shows clear evidence of the superlattice structure. Photoluminescence measurements of ZnSe epilayers show a dominant free‐exciton feature while the Zn1−xMnxSe epilayers exhibit two distinct photoluminescence peaks. The relative intensities of band‐to‐band transitions and Mn‐related transitions are somewhat comparable for the epilayers. However, the superlattices having ZnSe in the wells show virtually no Mn‐related emission regardless of the mole fraction of Mn in the barrier layers indicating significant carrier confinement. The intensity of the band‐to‐band emission is two orders of magnitude more intense for the superlattices than the ZnSe epilayer at 6.5 K. The superlattices show a red shift of the photoluminescence peak which can be explained in terms of shifts in the band gaps due to the presence of strains.