Wavelength-dependent optical degradation of green II–VI laser diodes

Abstract

In this letter we report on optical degradation studies on BeMgZnSe separate confinement quantum well laser structures for the blue-green spectral region. The wavelength of the incident light has been tuned from 3.81 down to 2.10 eV, corresponding to an energy range from above the band gap of the cladding layers down to below the band gap of the quantum well. The dominant degradation mechanism is initiated when electron hole pairs are created in the quantum well. Absorption of light in deep defect bands, e.g., of the p-type cladding material is negligible in these structures. The strain state of the quantum well is one possible driving force for the degradation. In this context, point defect propagation as well as a structural phase transition of the ZnCdSe quantum well are discussed.