Observation of stripe-direction dependence of threshold current density for AlGaInP laser diodes with CuPt-type natural superlattice in Ga0.5In0.5P active layer

Abstract

An anisotropy for threshold current densities for AlGaInP laser diodes with CuPt-type natural superlattice (NSL) in a Ga0.5In0.5P active layer, grown on a (001) GaAs substrate, was observed, for the first time. Threshold current densities (Jth) for laser diodes with stripes in the [1̄10] and [110] direction were 1.35 and 2.10 kA/cm2, respectively. The lasers with a weak NSL formation in the active layer showed a very small anisotropy in Jth. Stripe direction dependence of electroluminescence (EL) polarization properties were also observed for lasers with well-developed NSL. The anisotropies in Jth and EL polarization properties are attributed to the existence of the NSL in the active layer and the appearance asymmetry previously observed in the NSL.