Theoretical aspects of blue-green II-VI strained quantum well lasers

In this article, a theoretical overview of blue-green quantum well lasers with emphasis on ZnSe-based materials is presented. The effects of biaxial strain on the linear and nonlinear optical gains of a strained-layer II-VI quantum-well blue-green laser are studies with band mixing effects taken into account. The gain and gain-suppression coefficient of a strained quantum well laser are calculated from the complex susceptibility obtained by the density matrix formalism. The calculated gain of a CdZnSe-ZnSSe quantum well shows enhancement with increasing biaxial compressive strain in a quantum well. It is shown that the theoretical model employed in this study gives very good agreement on the L-I curve as well as the peak gain position of the quantum well structure with experiment. Feasibility of ZnSSe-MgZnSSe quantum wells with tensile strain and CdZnTe-ZnTe quantum wells with compressive strain on the optoelectronic device applications is also studied.