Enhanced performance of an InGaN–GaN light-emitting diode by roughening the undoped-GaN surface and applying a mirror coating to the sapphire substrate

An InGaN–GaN light-emitting diode (LED) with a roughened undoped-GaN surface and a silver mirror on the sapphire substrate was fabricated through a double transfer method. It was found that, at an injection current of 20mA, its luminance intensity was 100% larger than conventional LEDs. Its output power was 49% larger than conventional LEDs.