CdZnS-ZnS歪超格子のバンド不連続と一軸性応力効果

抄録

strain-induced band offsets of the conduction band and valence subbands in Cd_xZn_1-xs/Zns superlattices have theoretically been calculated on the basis of the model-solid theory taking into account of spin-orbit energy (Δ₈₀). The conduction and valence band offsets have been estimated as a function of the well layer thickness and Cd composition (x), and as a result the valence band offsets which are derived from heavy-hole and light-hole bands increase with both decreasing the well layer thickness and Zn composition. Effect of external uniaxial compressive stress (ε) on the band offsets indicates that the energy difference between the heavy-hole band in CdZnS well and the light-hole band in zns barrier increases monotonously with applied stress. On the other hand, that of light-hole bands shows a quadratic energy shift as a function of uniaxial stress and has a minimum energy value around εΔ/₆₀. It is pointed out that a large energy difference in uniaxial deformation potential constants between CdS and ZnS shows a unique behaviour which significantly modifies the electronic states in the CdZns-based quantum well structures under uniaxial stress.