Low efficiency droop of InGaN/GaN blue LEDs with super-lattice active structure

Abstract

We report the efficiency droop behaviors of InGaN/GaN blue LEDs with different thickness of GaN quantum barriers (QBs). The droop percentage from efficiency peak to 70 A/cm(2) is only about 10% as reducing the thickness of GaN QBs from 104 angstrom to 33 angstrom. A less carrier localization has been observed from wavelength dependent time resoled photoluminescence measurement as reducing the thickness of GaN QBs. The alleviation of droop percentage may due to more uniform distribution of electron and hole carrier in the active region, which resulted from super-lattice (SL) like active structure. The crystalline quality does not become worse from the results of v-pits density even thickness of GaN QBs is as low as 33 angstrom. The SL like active structure could be a potential structure to alleviate the efficiency droop for the application of solid state general lighting.