TIGHT-BINDING METHOD FOR QUANTUM-CONFINEMENT ENERGY CALCULATIONS IN THE CdSe/ZnSe MULTIPLE QUANTUM WELLS
We present an efficient method to calculate the quantum-confinement energy of charge carriers in the (ZnSe)(M)(CdSe)(N) (001) multiple quantum wells (MQW). The method is based on the 3D empirical sp(3)s* tight-binding models, which include the spin-orbit coupling. The method can handle large systems while it takes account of the band mixing caused by the strain and confinement. In these perspectives, it proves itself more reliable than the traditional effective-mass approach (EMA) by further generating more relevant information about the quantum states localized within the wells; in particular, the number of bound states and their energy levels and their corresponding wave functions were obtained based on more realistic physical models. The quantum-confinement energy, band gap energy, and band structures are studied versus the CdSe well width (N). The results are found to be comparable with those experimentally obtained using photoluminescence.
quantum wells semiconductor compounds ii-vi semiconductors