Reduction in Induced Strain in CdxZn1-xS Well Layers Using ZnS1-ySey Barrier Layers and Inhibition of Induced Strain due to Lattice Mismatch between MgzZn1-zS Cladding Layers and CdxZn1-xS/ZnS1-ySey Multiple Quantum Wells by Adjusting Mg Content

Abstract

The reduction in induced-strain effect in CdxZn1-xS-based quantum wells (QWs) is important for fabrication of laser diodes (LDs). To determine the effect of the reduction in the induced strain in a CdxZn1-xS well layer which combined with a ZnS1-ySey barrier layer. By reducing the induced strain, in this system, negative conduction and valence band offsets are obtained at large Se content y, band lineups are maintained to be Type I, and slightly low exciton binding and effective band gap energies are obtained. Under this condition, the confinement efficiencies of electron and holes slightly decreases. We propose that a CdxZn1-xS/ZnS1-ySey multiple quantum well (MQW) is sandwiched between two MgzZn1-zS cladding layers. The energy difference between ZnS1-ySey and MgzZn1-zS band gaps increases with increasing Mg content z. MgzZn1-zS cladding layers are lattice-matched to CdxZn1-xS/ZnS1-ySey MQWs by adjusting z, and then the induced strain due to the MgzZn1-zS cladding layers is removed.