Effect of InGaN quantum dot size on the recombination process in light-emitting diodes

The effect of InGaN quantum dot (QD) size on the performance of light-emitting diodes (LEDs) was investigated by varying the QD size from 1.32 to 2.81 nm. The electroluminescence peak of the LEDs containing small QDs (1.32 nm) was redshifted with increasing input current while that of large QDs (2.81 nm) was blueshifted up to 40 mA due to the screening effect of the piezoelectric field. The optical output power of LEDs fabricated with small QDs was much higher compared to those with large QDs. These results were attributed to a weaker piezoelectric field and enhanced quantum confinement in small QDs.