Influence of GaNAs strain compensation layers upon annealing of GaIn(N)As/GaAs quantum wells

Abstract

GaIn(N)As/GaAs and GaIn(N)As/GaNAs/GaAs quantum well samples, with and without GaNAs strain-compensating layers (SCL), were grown on GaAs (001) substrates by molecular beam epitaxy. Photoluminescence (PL) was used to study the effects of the GaNAs SCL on the properties of the Ga(In)NAs QWs upon annealing. It is found that an extra blue-shift (Δ E = 5.2 meV) in the PL emission from the GaInNAs QW sample at the initial annealing stage ( t ann = 40 s) was induced by the GaNAs SCLs. However, for the GaInAs QW sample, the blue-shift induced by GaNAs SCL is only 1.1 meV. As the annealing time was increased, the blue-shift of both GaInNAs and GaInAs QWs showed saturations at 16 meV and 8 meV, respectively. The PL blue-shifts were much enhanced by inserting GaNAs SCLs showing a non-saturable behavior. X-ray diffractions from the strain compensated GaIn(N)As QWs before and after annealing show no N atom diffusion but Ga/In atom interdiffusion across the QW interfaces. The Ga/In atom interdiffusion caused by annealing was also confirmed by high-resolution transmission electron microscopy from the GaInNAs/GaAs QW sample.