N-polar InGaN nanowires: breaking the efficiency bottleneck of nano and micro LEDs

The efficiency of conventional quantum well light-emitting diodes (LEDs) decreases drastically with reducing areal size. Here we show that such a critical size scaling issue of LEDs can be addressed by utilizing N-polar InGaN nanowires. We studied the epitaxy and performance characteristics of N-polar InGaN nanowire LEDs grown on sapphire substrate by plasma-assisted molecular beam epitaxy. A maximum external quantum efficiency ∼ 11 % was measured for LEDs with lateral dimensions as small as 750 nm directly on wafer without any packaging. The effect of electron overflow and Auger recombination on the device performance is also studied. This work provides a viable approach for achieving high-efficiency nano and micro LEDs that were not previously possible.