InGaN/GaN self-organized quantum dot green light emitting diodes with reduced efficiency droop

High density (2-5x10(10) cm(-2)) self-organized InGaN/GaN quantum dots were grown by plasma-assisted molecular beam epitaxy. Room temperature photoluminescence shows that the quantum dots have strong emission ranging from 430 to 524 nm. The internal quantum efficiency of dots emitting at 500 nm was determined to be 32% by temperature dependent photoluminescence measurements. A recombination lifetime of 0.57 ns is derived from time resolved photoluminescence measurements. These superior optical properties are attributed to a small piezoelectric field in the quantum dots. Light emitting diodes fabricated with the InGaN/GaN quantum dots and emitting at lambda=524 nm demonstrate a small blueshift with current injection and reduced efficiency droop. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3460921]