Liu Mengling, Zhao Jie, Zhou Shengjun, Gao Yilin, Hu Jinfeng, Liu Xingtong, Ding Xinghuo
Key Laboratory of Hydraulic Machinery Transients (Wuhan University), Ministry of Education, Wuhan 430072, China.
Center for Photonic and Semiconductor, School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
Nanomaterials (Basel). 2018 Jun 21;8(7):450. doi: 10.3390/nano8070450.
Despite the fact that an InGaN/GaN superlattice (SL) is useful for enhancing the performance of a GaN-based light-emitting diode (LED), its role in improving the efficiency of green LEDs remains an open question. Here, we investigate the influence of a V-pits-embedded InGaN/GaN SL on optical and electrical properties of GaN-based green LEDs. We recorded a sequence of light emission properties of InGaN/GaN multiple quantum wells (MQWs) grown on a 0- and 24-pair InGaN/GaN SL by using scanning electron microscopy (SEM) in combination with a room temperature cathodoluminescence (CL) measurement, which demonstrated the presence of a potential barrier formed by the V-pits around threading dislocations (TDs). We find that an increase in V-pit diameter would lead to the increase of V-pit potential barrier height. Our experimental data suggest that a V-pits-embedded, 24-pair InGaN/GaN SL can effectively suppress the lateral diffusion of carriers into non-recombination centers. As a result, the external quantum efficiency (EQE) of green LEDs is improved by 29.6% at an injection current of 20 mA after implementing the V-pits-embedded InGaN/GaN SL layer. In addition, a lower reverse leakage current was achieved with larger V-pits.
尽管氮化铟镓/氮化镓超晶格（SL）有助于提高基于氮化镓的发光二极管（LED）的性能，但其在提高绿色LED效率方面的作用仍是一个悬而未决的问题。在此，我们研究了嵌入V形坑的氮化铟镓/氮化镓超晶格对基于氮化镓的绿色LED光学和电学性能的影响。我们通过结合扫描电子显微镜（SEM）和室温阴极发光（CL）测量，记录了在0对和24对氮化铟镓/氮化镓超晶格上生长的氮化铟镓/氮化镓多量子阱（MQW）的一系列发光特性，这证明了在穿透位错（TD）周围由V形坑形成的势垒的存在。我们发现V形坑直径的增加会导致V形坑势垒高度的增加。我们的实验数据表明，嵌入V形坑的24对氮化铟镓/氮化镓超晶格可以有效地抑制载流子向非复合中心的横向扩散。结果，在实施嵌入V形坑的氮化铟镓/氮化镓超晶格层后，绿色LED在20 mA注入电流下的外部量子效率（EQE）提高了29.6%。此外，较大的V形坑实现了较低的反向漏电流。
