Optimization of InGaN/GaN multiple quantum well layers by a two-step varied-barrier-growth temperature method

We report the effect of different temperature profiles on the quality of the InGaN/GaN multiple quantum well (MQW) structures by employing photoluminescence (PL) and atomic force microscopy (AFM). We adopted a two-step varied-barrier-growth temperature method to improve the structural and optical properties of the InGaN/GaN MQW layers. The low-temperature GaN barrier layer was introduced to reduce the desorption rate of the indium atoms of the InGaN well, and then the high-temperature GaN barrier was grown to reduce the defects of InGaN/GaN MQWs. When the width of the low-temperature GaN barrier was 50 and the high-temperature GaN barrier was grown at 1000 °C, the defect and surface roughness were significantly reduced, especially with a reduction in the depth of V-defect as low as 20 .