Enhanced performances of InGaN-based light-emitting diode by a micro-roughened p-GaN surface using metal clusters

InGaN-based light-emitting diode with a micro-roughened top surface using the metal clusters as wet etch masks was investigated. The forward voltage, V-F, at 20 mA for InGaN/GaN MQW LED chip with a micro-roughened top surface was improved compared to that of the conventional InGaN/GaN MQW LED chip. This result could be attributed to the improved metal contact on p-GaN due to an increased contact area between the metal and p-GaN layer. Furthermore, the light-output power for InGaN/GaN MQW LED chip with a micro-roughened top p-GaN surface was increased compared to that for the conventional InGaN/GaN MQW LED chip. This indicate that the scattering of photons emitted in the MQW active layer was much enhanced at the micro-roughened top p-GaN surface of LED due to the angular randomization of photons inside the LED structure, resulting in an increase in the probability of escaping from the LED structure.