MBE growth of II-VI epilayers and QW structures on hexagonal ZuCdS and CdSSe substrates

摘要

ZnTe, ZnSe layers and ZnCdTe/ZnTe, ZnCdSe/ZnSe quantum well structures were grown on hexagonal Zn0.05Cd0.95S(0001) and CdS0.85Se0.15(11 (2) under bar0) by molecular beam epitaxy and studied by cathodoluminescence (CL), photoreflection, and X-ray diffraction. The structures grown on the (11 (2) under bar0) substrates had rough surface while the structures grown on the (0001) substrate were mirror-like. All structures were cubic. In the ZnSe based structures, the <111> and <(1) under bar 10> lattice directions of epilayers coincided with the <0001> and <11 (2) under bar0> directions of CdZnS(0001) substrate, respectively, High mismatching leaded to a lattice relaxation of these epilayers by introduction of misfit dislocations. This was the reason of low CL intensity. In spite of higher mismatching, the ZnTe based epilayers grown on (0001) substrates had more perfect lattice structure and more intense CL than ZnSe based epilayers. Cubic lattice of ZnTe was found to be rotated approximately by 15degrees around the <111> direction coincided with the <0001> direction of the (0001) substrate. It was proposed that a geometrical lattice matching took place at epitaxy of ZnTe on the CdZnS(0001). [References: 8]