Influence of electrostatic confinement on optical gain in GaInNAs quantum-well lasers

There remains controversy surrounding the cause of the magnitude and temperature sensitivity of the threshold current density of 1.3-μm GaInNAs quantum-well (QW) lasers, with several authors attributing the strong temperature sensitivity to hole leakage, due to the relatively low valence band offset in GaInNAs/ GaAs QW structures. We use a Poisson solver along with a ten-band k.p Hamiltonian to calculate self-consistently the influence of electrostatic confinement on the optical gain in such lasers. We find that the inclusion of such effects significantly reduces the hole leakage effect, with the electrostatic attraction of the electrons significantly increasing the binding of heavy holes in the QW region. We conclude by comparison with previous theoretical and experimental studies that the room temperature threshold current is generally dominated by monomolecular recombination, while the temperature sensitivity can be explained as predominantly due to Auger recombination.