Investigations of lateral curent injection lasers: internal operating mechanisms and doping profile engineering

摘要

Lateral current injection laser gown on semi-insulating substrates are natural candidates for monolithic optoelectronic integration. The lateral injection geometry is demonstrated herein to differe quanitatively from the coventional vertidal injection paradigm in ways which are physically interesting and technologically important. By considering the physics of ambipolar diffusion th in presence of a position-dependent rate of recombination resulting from non-radiative, spontaneous, and stimulated processes, we predict that shifting the location of dopants relative to the optical mode may significantly improve the ouput characteristics of the device. Our 2D numerical modeling confirms this expectation, predicting that a factor of 1.5 improvement in the differential quantum efficiency of the device simulated may be obtained by shifting the lateral p-i junction 0.6 mu m toward trhe centre of the 1.5 mu ridge. We predict quantitatively and explain physically one reason for pronounced rool-off in the L-I characteris of devices reported in the literature, and demon-strate that shifting the doping front may reduce this non-linearity dramatically. We conclude as to the need to approach lateral curent injeftion as a qualitatively different problem from conventional vertical injection in order for the tremendous potential of these devices to be realized fully.