OPTICAL AND ELECTRICAL DEGRADATIONS OF GAAS-BASED LASER-DIODES GROWN ON SI SUBSTRATES

A GaAs-based laser diode grown on a Si-substrate suffers from degradation, which results from the deterioration of electrical and optical characteristics. An initial deterioration of a p-n junction is observed in a reverse current-voltage (I-V) characteristic, and becomes ohmic-like under a higher ambient temperature and a larger forward current. Electroluminescence observation shows that the optical deterioration is caused by the growth of dark spot regions, which act as nonradiative recombination regions. The deterioration of the I-V characteristic is probably due to defect-accelerated impurity diffusion because the growth of GaAs/Si involves a high dislocation density, a large tensile stress and a large amount of Si near the GaAs/Si interface.