Dong Peng, Yan Jianchang, Zhang Yun, Wang Junxi, Geng Chong, Zheng Haiyang, Wei Xuecheng, Yan Qingfeng, Li Jinmin
Opt Express. 2014 Mar 10;22 Suppl 2:A320-7. doi: 10.1364/OE.22.00A320.
Nanopillar AlGaN/GaN multiple quantum wells ultraviolet light-emitting diodes (LEDs) were fabricated by nanosphere lithography and dry-etching. The optical properties of the nanopillar LEDs were characterized by both temperature-dependent and time-resolved photoluminescence measurements. Compared to an as-grown sample, the nanopillar sample has a PL emission peak blue-shift of 7 meV, a 42% enhanced internal quantum efficiency at room temperature and a reduced radiative recombination lifetime from 870 picosecond to 621 picosecond at 7K. These results are directly from the suppressed quantum confined stark effect that is due to the strain relaxation in the nanopillar MQWs, further revealed by micro-Raman measurement. Additionally, finite-difference time domain simulation also proves better light extraction efficiency in the nanopillar LEDs.
通过纳米球光刻和干法蚀刻制备了纳米柱AlGaN/GaN多量子阱紫外发光二极管（LED）。通过温度相关和时间分辨光致发光测量对纳米柱LED的光学特性进行了表征。与生长态样品相比，纳米柱样品的光致发光发射峰蓝移了7 meV，室温下内部量子效率提高了42%，在7K时辐射复合寿命从870皮秒降低到621皮秒。这些结果直接源于纳米柱多量子阱中由于应变弛豫而受到抑制的量子限制斯塔克效应，微拉曼测量进一步揭示了这一点。此外，时域有限差分模拟也证明了纳米柱LED具有更好的光提取效率。
