Tunable photoluminescence of uniformly doped short-period GaAs doping superlattices

Abstract

Doping or n-i-p-i superlattices are promising materials for tunable light sources. Long-period GaAs doping superlattices have exhibited wide tunability in the photoluminescence (PL) peak energy versus excitation intensity,1 but photopumped lasing has been observed only at high excitation, where excess carriers completely screen the superlattice space-charge potential.2 By contrast, short-period superlattices possess a smaller degree of luminescence tunability yet exhibit larger oscillator strengths because of the greater overlap between electron and hole wave functions in the n- and p-type layers, respectively. A desirable goal is to achieve lasing at carrier densities below the value that completely screens the superlattice potential, thereby permitting tunability of the radiation. We have investigated the limits of tunability in uniformly doped short-period GaAs doping superlattices and present results of low-temperature photoluminescence.