2 MeV-He ion channeling studies of MOVPE-grown GaInNAs single quantum wells

The channeling technique of 2 MeV-He+ ions is applied to analyze the lattice structure of GaInNAs quantum wells sandwiched by GaAs barrier layers. The structure-sensitive channeling measurements reveal that the GaInNAs layer contains significant lattice distortion even after post-growth annealing at high temperatures. However, there exist no well-defined point defects such as tetrahedral interstitials. Our results suggest that the interstitial In atoms diffuse by annealing effect and we roughly estimate that the fraction of interstitial In atoms is reduced by ∼10% after annealing. Therefore, we demonstrate that the drastic improvement of the optical characteristics originates from the In diffusion by the annealing