Enhance the electroluminescence efficiency of InGaN/GaN multiple quantum wells by optimizing the growth temperature of GaN barriers

Abstract

Three InGaN/GaN MQWs samples with different QB layers growth temperatures were grown on sapphire substrate by metalorganic chemical vapor deposition (MOCVD). It is found that the electroluminescence intensity increases first and then decreases with increasing growth temperature of GaN barrier layers when the growth temperature increases from 800 °C to 880 °C. The XRD and AFM measurements show that a better interface quality exists in InGaN/GaN MQW whose GaN barrier layers grown at a higher temperature. However, when the growth temperature of GaN barriers is too high, a quality degradation of QWs will occur for underlying InGaN well layers, resulting in a decrease of the luminous intensity of the active region. Finally, we proposed that using three temperature growth scheme could improve the electroluminescence efficiency of the active region compared to conventional dual-temperature growth method.