Department of Electrical and Computer Engineering, McGill University , 3480 University Street, Montreal, Quebec H3A 0E9, Canada.
Nano Lett. 2013;13(11):5437-42. doi: 10.1021/nl4030165. Epub 2013 Oct 3.
We have examined the carrier injection process of axial nanowire light-emitting diode (LED) structures and identified that poor carrier injection efficiency, due to the large surface recombination, is the primary cause for the extremely low output power of phosphor-free nanowire white LEDs. We have further developed InGaN/GaN/AlGaN dot-in-a-wire core-shell white LEDs on Si substrate, which can break the carrier injection efficiency bottleneck, leading to a massive enhancement in the output power. At room temperature, the devices can exhibit an output power of ~1.5 mW, which is more than 2 orders of magnitude stronger than nanowire LEDs without shell coverage. Additionally, such phosphor-free nanowire white LEDs can deliver an unprecedentedly high color rendering index of ~92-98 in both the warm and cool white regions, with the color rendering capability approaching that of an ideal light source, i.e. a blackbody.
我们研究了轴向纳米线发光二极管（LED）结构的载流子注入过程，确定由于表面复合率较高，导致载流子注入效率低下，这是无荧光粉纳米线白光 LED 输出功率极低的主要原因。我们进一步在 Si 衬底上开发了 InGaN/GaN/AlGaN 点在线核壳结构的白光 LED，其可以打破载流子注入效率的瓶颈，从而显著提高输出功率。在室温下，器件的输出功率约为 1.5mW，比没有壳层覆盖的纳米线 LED 强 2 个数量级以上。此外，这种无荧光粉的纳米线白光 LED 在暖白光和冷白光区域都能提供前所未有的高显色指数（约 92-98），显色能力接近理想光源（即黑体）。
