Study of Defect and Spectral Characteristics of Light Emitting Diodes with Multiple InGaN/GaN Quantum Wells on Patterned Sapphire Substrates

In order to investigate the influence of the structure and morphology of patterned sapphire substrates on the luminescent performance of GaN-based light-emitting diodes, light-emitting diodes with the same structure were prepared on flat and patterned sapphire substrates, respectively. The reasons for the formation of dislocations and V-pits in the devices were analyzed, and the current and luminescent characteristics of two devices with different substrates were tested and compared. The relationship between the luminescent characteristics and internal defects in the devices was also analyzed. Research has shown that patterned substrates significantly reduce the dislocation density inside light-emitting diodes, and the light output power and external quantum efficiency of light-emitting diodes grown on patterned substrates are significantly improved. However, dislocation may not be the main reason for efficiency drop.