Thermal annealing of molecular beam epitaxy-grown InGaN/GaN single quantum well

摘要

The effect of thermal annealing on In_(0.56)Ga_(0.75)N/GaN quantum wells grown by molecular beam epitaxy at 550 ℃ is investigated. A strong increase in the 300 K photoluminescence (PL) intensity is observed for samples annealed at 880 ℃, while degradation occurs for higher temperatures. The improvement of the optical properties is ascribed to higher internal quantum efficiency (IQE), as indicated by temperature-dependent and time-resolved PL experiments. The effect of carrier localization due to possible quantum dot formation via indium clustering is ruled out based on high-resolution transmission electron microscopy imaging. IQE improvement is thus attributed to a reduction of point defects upon annealing.