Department of Physics, Inha University, Incheon 22212, Korea.
LG Electronics Advanced Research Institute, Seoul 06763, Korea.
Sci Rep. 2017 Apr 12;7:44814. doi: 10.1038/srep44814.
We investigated the efficiency droop and polarization-induced internal electric field of InGaN blue light-emitting diodes (LEDs) grown on silicon(111) and c-plane sapphire substrates. The efficiency droop of the LED sample grown on silicon substrates was considerably lower than that of the identically fabricated LED sample grown on sapphire substrates. Consequently, the LED on silicon showed higher efficiency at a sufficiently high injection current despite the lower peak efficiency caused by the poorer crystal quality. The reduced efficiency droop for the LED on silicon was attributed to its lower internal electric field, which was confirmed by reverse-bias electro-reflectance measurements and numerical simulations. The internal electric field of the multiple quantum wells (MQWs) on silicon was found to be reduced by more than 40% compared to that of the MQWs on sapphire, which resulted in a more homogenous carrier distribution in InGaN MQWs, lower Auger recombination rates, and consequently reduced efficiency droop for the LEDs grown on the silicon substrates. Owing to its greatly reduced efficiency droop, the InGaN blue LED on silicon substrates is expected to be a good cost effective solution for future lighting technology.
我们研究了在硅（111）和 c 面蓝宝石衬底上生长的氮化铟镓（InGaN）蓝光发光二极管（LED）的效率衰减和偏振诱导的内电场。在硅衬底上生长的 LED 样品的效率衰减明显低于在蓝宝石衬底上生长的相同结构的 LED 样品。因此，尽管峰值效率较低，由于晶体质量较差，但 LED 在足够高的注入电流下显示出更高的效率。硅上的 LED 效率衰减降低归因于其较低的内电场，这通过反向偏压电反射测量和数值模拟得到了证实。与蓝宝石上的 MQWs 相比，硅上的多量子阱（MQWs）的内电场降低了超过 40%，这导致 InGaN MQWs 中载流子分布更加均匀，俄歇复合率降低，从而降低了在硅衬底上生长的 LED 的效率衰减。由于其效率衰减大大降低，硅衬底上的 InGaN 蓝光 LED 有望成为未来照明技术的一种具有成本效益的解决方案。
