The fabrication of ZnS/GaP heterostructure and a novel A1BA2-type ZnS/ZnSTe/ZnS quantum well structure has been demonstrated by the molecular beam epitaxy technique on GaP(001) substrates. We have studied the structural properties of these structures using the combination of high resolution x-ray diffraction technique and a computer simulation program based on Takagi-Taupin dynamical theory. In particular, the Poisson ratio of ZnS (001) was determined to be 0.341 in this study. The approach used in this work provides ability to determine the composition of the ZnSTe quantum well with high accuracy, and in principle, could be applied to investigate the structural properties of similar multilayer structures....[ Read more ]

The fabrication of ZnS/GaP heterostructure and a novel A1BA2-type ZnS/ZnSTe/ZnS quantum well structure has been demonstrated by the molecular beam epitaxy technique on GaP(001) substrates. We have studied the structural properties of these structures using the combination of high resolution x-ray diffraction technique and a computer simulation program based on Takagi-Taupin dynamical theory. In particular, the Poisson ratio of ZnS (001) was determined to be 0.341 in this study. The approach used in this work provides ability to determine the composition of the ZnSTe quantum well with high accuracy, and in principle, could be applied to investigate the structural properties of similar multilayer structures.

In addition to structural characterization, the quantum confinement effects on the optical properties of the ZnS/ZnSTe/ZnS quantum well structure have also been studied by performing photoluminescence measurements from 300K down to 77K on the quantum well sample as well as a ZnSTe single layer with Te composition x close to that of the quantum well. The emissions of the Te isoelectronic centers of the well layer in the quantum well structure were found to be blue-shifted more than 0.4eV and we therefore believe that both the energy states of the Te isoelectronic centers (IECs) and the continuum energy bands of the alloy of the well layer are modified. Moreover, the temperature dependence of the emission characteristics of the quantum well structure was observed to be clearly distinctive from that of the single layer. We believe that these observations are somehow related to the quantum confinement effects on the band structure, the IECs' states and the energy transfer processes in the quantum well structure.