Influence of polarization field on the lasing properties of III-nitride quantum wells

A theoretical investigation of the effect of polarization-induced fields on the optoelectronic properties of a 3 nm In0.2Ga0.8N/GaN single quantum well has been carried out via a self-consistent solution of Schrödinger–Poisson equations within the effective mass approximation. A pronounced, non-monotonic dependence of the threshold current density Jth on the well width has been found due to the enhanced quantum-confined Stark effect. Furthermore, the dependence of threshold current density on the value of the electric field in the well was examined. The threshold current in the 3 nm In0.2Ga0.8N/GaN well is higher by a factor of 2–5 compared to an identical well with zero internal field Eint. We show that the ability to reduce or eliminate internal fields appears attractive for the improvement of the optoelectronic properties of nitride-based laser diodes and one of achieving this is by using field-compensated quaternary InAlGaN/GaN heterostructures.