Control of dopant distribution profiles in GaInP laser diodes with Mg- and Se-doped AlInP cladding layers

Abstract

High doping levels on either side of a double heterostructure laser are required for optimal performance and temperature stability, especially in the AlGaInP material system. However, in most cases these are accompanied by strong diffusion during growth, shifting the p–n junction and damaging the active zone. We investigated the possibiltity of suppressing the diffusion towards the active zone by introducing thin intermediate layers of different materials and doping levels as well as short-period superlattices. Using SIMS measurements we found that the non indium-containing layers GaP and GaAs are suitable to slow down diffusion of the magnesium on the p-side and produce a rather steep dopant front. On the other hand, the presence of the additional interfaces seems to have a negative influence on the electrical properties of the device, resulting in increased threshold currents and reduced quantum efficiencies. To determine the decisive factors for this behavior, additional optical measurements were done on the samples. In another approach we investigated n-doped AlInP intermediate layers and their influence on the magnesium profile.