Optical gain and threshold current densities in multiple quantum wire lasers were calculated, while taking account of the effect of strain. It was found that tensile-strained quantum wires yielded lower threshold current densities than did compressively strained or unstrained structures. The estimated threshold current density for a defect-free tensile-strained ZnCdSe-ZnMgSSe quantum wire laser, on an InP substrate, was 58A/cm2. Exciton transitions aided in lowering the threshold current density, which was adversely affected by the presence of dislocations and surface states. It was found that the threshold current density increased to 435A/cm2 upon assuming trapping levels of 1017/cm3 which were due to dislocations and surface states. Upon taking account of exciton transitions, the threshold current density was reduced to 79A/cm2; while assuming the same trap density.

W.Huang, F.Jain: Journal of Applied Physics, 1997, 81[10], 6781-5