Improvement in the optical and structural properties of InGaN/GaN multiple quantum wells by indium predeposition

Indium predeposition prior to the growth of InGaN well layers was found to significantly improve the optical properties of InGaN/GaN multiple quantum wells (MQWs). photoluminescence and ultraviolet-visible absorption spectroscopy measurements showed a remarkable decrease in the Stokes shift with increasing indium predeposition time. High resolution x-ray diffraction measurements revealed a significant improvement in the interface quality of the MQWs. These results indicate that indium predeposition improves the uniformity of the indium composition in InGaN well layers, resulting in the formation of nearly perfect square potential wells in MQWs.