Molecular Beam Epitaxial Growth of Hexagonal CdSe and ZnCdSe on Cubic GaAs(111)B Substrates

Conditions for obtaining hexagonal wurtzite CdSe and ZnCdSe epilayers were investigated by molecular beam epitaxy on cubic zincblende GaAs(111)B substrates. The wurtzite CdSe epilayers tended to grow under high VI/II beam-pressure ratios and low growth temperatures. The growing axis of the ZnCdSe epilayer grown at 280°C was tilting toward the Zn effusion cell position. The tilting and the crystallinity were improved by increasing the growth temperature from 280 to 320°C. The wurtzite-inclusion rates in the ZnCdSe epilayers increased with increasing Cd composition of the epilayers and exceeded 90% at the Cd composition of 0.57. The wurtzite-inclusion rates in the Zn 0.8 Cd 0.2 Se epilayers increased with increasing VI/II beam-pressure ratios and saturated at above the VI/II pressure ratio of approximately 6.