Li Yufeng, Tang Weihan, Zhang Ye, Guo Maofeng, Li Qiang, Su Xilin, Li Aixing, Yun Feng
Shaanxi Provincial Key Laboratory of Photonics and Information Technology, Xi'an Jiaotong University, Xi'an 710049, China.
Solid-State Lighting Engineering Research Center, Xi'an Jiaotong University, Xi'an 710049, China.
Nanomaterials (Basel). 2019 Apr 18;9(4):633. doi: 10.3390/nano9040633.
The size of the V-defects in the GaN/InGaN-based quantum wells blue light-emitting diode (LED) was intentionally modified from 50 nm to 300 nm. High resolution photoluminescence and electroluminescence of a single large V-defect were investigated by near-field scanning optical microscopy. The current distribution along the {10-11} facets of the large defect was measured by conductive atomic force microscopy. Nearly 20 times the current injection and dominant emission from bottom quantum wells were found in the V-defect compared to its vicinity. Such enhanced current injection into the bottom part of quantum wells through V-defect results in higher light output power. Reduced external quantum efficiency droops were achieved due to more uniform carrier distribution. The un-encapsulated fabricated chip shows light output power of 172.5 mW and 201.7 mW at 400 mA, and external quantum efficiency drop of 22.3% and 15.4% for the sample without and with large V-defects, respectively. Modified V-defects provide a simple and effective approach to suppress the efficiency droop problem that occurs at high current injection, while improving overall quantum efficiency.
基于GaN/InGaN量子阱的蓝光发光二极管（LED）中V型缺陷的尺寸被有意地从50纳米修改为300纳米。通过近场扫描光学显微镜研究了单个大V型缺陷的高分辨率光致发光和电致发光。通过导电原子力显微镜测量了大缺陷沿{10-11}面的电流分布。与V型缺陷附近相比，在V型缺陷中发现注入电流增加了近20倍，并且底部量子阱有主导发射。通过V型缺陷向量子阱底部增强的电流注入导致更高的光输出功率。由于载流子分布更加均匀，实现了外部量子效率下降的降低。未封装的制造芯片在400毫安时的光输出功率分别为172.5毫瓦和201.7毫瓦，对于没有大V型缺陷和有大V型缺陷的样品，外部量子效率下降分别为22.3%和15.4%。修改后的V型缺陷提供了一种简单有效的方法来抑制在高电流注入时出现的效率下降问题，同时提高整体量子效率。
