ZnSe-based heterostructures for blue-green lasers

We review the current status of research activity on ZnSe-based heterostructures for blue-green laser diodes (LDs), focusing on a few selected critical issues. Early investigations on defect microstructures allowed to strongly enhance the lifetime of LDs. However, the LD lifetime seems to saturate now, and we point out that the model proposed for explaining the degradation of LD does not predict such a saturation. Next, we detail the mechanisms responsible for carrier compensation in p-type ZnSe and we survey the properties of ZnMgSSe and ZnMgBeSe wide bandgap quaternary alloys which are used as cladding layers in LDs. We emphasize that the low p-type dopability of ZnSe and related materials has a dramatic impact on the performance of LDs in terms of emitted wavelength as well as device lifetime. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.