Improvement of InGaN/GaN light emitting diode performance with a nano-roughened p-GaN surface by excimer laser-irradiation

In this paper, we reported the InGaN/GaN light emitting diode (LED) with a nano-roughened top p-GaN surface which caused by KrF excimer laser-irradiation. Comparing with the conventional LED, the brightness of InGaN/GaN light emitting diode (LED) was raised by a factor of 1.25 at 20 mA after KrF excimer laser-irradiation (250 mJ cm−2 at 248 nm for 25 ns). Meanwhile, the operation voltage of InGaN/GaN LED was reduced from 3.55 to 3.3 V at 20 mA with 29% reduction in the series resistance. The causes for the brightness increase can be attributed to laser-irradiation induced nano-roughening of p-GaN surface. The reduction in the series resistance can be attributed to the increased contact area of nano-roughened surface and higher hole concentration after laser-irradiation.