Effect of V-shaped defects on structural and optical properties of AlGaN/InGaN multiple quantum wells

We have investigated the correlation between V-shaped defect formation and the optical properties of AlGaN/(In) GaN multiple quantum wells ( MQWs) grown under different growth conditions and then demonstrated the characteristics of fabricated ultraviolet ( UV) light emitting diodes ( LEDs). From the temperature-dependent photoluminescence ( PL) measurement, the internal quantum efficiency for 300 K was obtained as 43.6% for a sample with a low density of V-defects in a MQW and 13.7% for a sample with a high density of V-defects. The carrier lifetime based on the time resolved PL measurement at room temperature was 0.32 ns for a sample with a high density of V-defects and 1.26 ns for a sample with a low density of V-defects. And we also found that the density of V-defects affected the external quantum efficiency and wall plug efficiency of the fabricated UV LEDs.