MBE growth and characterization of hexagonal ZnCdSe layers on GaAs(111)-A and -B substrates

Zn0.5Cd0.5Se epilayers were grown on GaAs(111)-A and -B substrates by MBE. We investigated how the polarity of the substrate affects both the epilayer crystalline structure and quality. It was found that the epilayers consisted of hexagonal and cubic phases independent of the substrate polarity. The hexagonal phase content. in the epilayers tended to be minimal at a growth temperature around 300degreesC; it increased with decreasing growth temperature in the range of 200-300degreesC and increased again above 300degreesC. The hexagonal phase content in the epilayers grown on the (111)-B face was relatively high compared with that on the (111)-A face. However, the crystalline quality of the epilayers grown on the (111)-A face was much better. Furthermore, the hexagonal phase content increased for both (111)-A and -B faces with increasing VI/II beam flux ratio. In that case, the epilayer quality was improved on (111)-A face, though it tended to become poor on (111)-B face.