Cathodoluminescence study of degradation in ZnSe-based semiconductor laser diodes

After continuous-wave operation of ZnSe-based semiconductor laser diodes, the degradation of these devices was investigated using cathodoluminescence imaging and spectroscopy. Inside the stripe region, i.e., the carrier injection area, there were several dots in which the peak wavelength of emission from a ZnCdSe strained quantum well (QW) shifted with time to a shorter wavelength (blueshift). We consider that the blueshift is Due to Cd/Zn interdiffusion. This interdiffusion is enhanced by the electron-hole recombination process (recombination enhanced interdiffusion). Furthermore, there were dark line defects (DLDs) in the [100] direction, outside the stripe region and running away from the dots, having emission with a blueshift. The peak wavelength of emission from the QW in the DLDs shifted to a longer wavelength (redshift). We consider that the redshift is due to the relaxation of strain in the QW by existing defects, which may originate in the blueshift dots and move outside the stripe region. (C) 1998 American Institute of Physics.