Variations of energy-band-diagrams with forward bias voltages for step-like separate-confinement-heterostructure for single-quantum-well lasers

The variations of energy-band-diagrams with forward bias voltages for step separate-confinement-heterostructure single quantum-well lasers are investigated by numerically solving the semiconductor device equations with two band parameters described by the generalized Einstein relation and various position-dependent parameters for the materials. The effects of bandgap shrinkage are included. By examining band diagrams, it was found that the potential profiles of the quantum wells with respect to the centers of the wells are: (1) symmetric at high injection; (2) tilted at low injection; and (3) almost flat with reasonable injection. In the intrinsic regions, the difference of the quasi-Fermi potentials can be well approximated by the applied voltage. >