Indium gallium nitride-based ultraviolet, blue, and green lightemitting diodes functionalized with shallow periodic hole patterns

In this study, we investigated the improvement in the light output power of indium gallium nitride ( InGaN)- based ultraviolet ( UV), blue, and green light- emitting diodes ( LEDs) by fabricating shallow periodic hole patterns ( PHPs) on the LED surface through laser interference lithography and inductively coupled plasma etching. Noticeably, different enhancements were observed in the light output powers of the UV, blue, and green LEDs with negligible changes in the electrical properties in the light output power versus current and current versus voltage curves. In addition, confocal scanning electroluminescence microscopy is employed to verify the correlation between the enhancement in the light output power of the LEDs with PHPs and carrier localization of InGaN/ GaN multiple quantum wells. Light propagation through the PHPs on the UV, blue, and green LEDs is simulated using a threedimensional finite- difference time- domain method to confirm the experimental results. Finally, we suggest optimal conditions of PHPs for improving the light output power of InGaN LEDs based on the experimental and theoretical results.