Origin and nature of a native defect acting as non-radiative center in GaInN/GaN quantum well structures

Controlling the point defects that contribute to non-radiative recombination in GaInN/GaN quantum well structures has become more important recently. We have varied the growth temperature, thickness, and V/III ratio of the buffer layer and studied their influence on the non-radiative lifetime of the quantum well (QW). The results suggest that the point defect density in the QW can be reduced by controlling the defect formation and diffusion mechanisms. The point defect that is both diffusing and acting as a non-radiative center is likely a native defect, more specifically, a nitrogen vacancy. The likely sources of the vacancies are primarily the nucleation layer and the GaN substrate, in the case of heteroepitaxy and homoepitaxy, respectively, and secondarily the growing surface of subsequent layers, depending on the growth conditions.