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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.