Lee Seungmin, Kim Jongmyeong, Oh Jehong, Ryu Jungel, Hwang Kyungwook, Hwang Junsik, Kang Sungjin, Choi Jun Hee, Sim Young Chul, Cho Yong-Hoon, Chung Tae Hoon, Jeong Tak, Park Yongjo, Yoon Euijoon
Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Korea.
Samsung Advanced Institute of Technology, Suwon, 16678, Korea.
Sci Rep. 2020 May 5;10(1):7506. doi: 10.1038/s41598-020-64478-3.
A discrete core-shell-like micro-light-emitting diode (micro-LED) array was grown on a 100 nm-thick sapphire nano-membrane array without harmful plasma etching for chip singulation. Due to proper design for the sapphire nano-membrane array, an array of multi-faceted micro-LEDs with size of 4 μm × 16 μm was grown. Threading dislocation density in the micro-LED formed on sapphire nano-membrane was reduced by 59.6% due to the sapphire nano-membranes, which serve as compliant substrates, compared to GaN formed on a planar substrate. Enhancements in internal quantum efficiency by 44% and 3.3 times higher photoluminescence intensity were also observed from it. Cathodoluminescence emission at 435 nm was measured from c-plane multiple quantum wells (MQWs), whereas negligible emissions were detected from semi-polar sidewall facets. A core-shell-like MQWs were formed on all facets, hopefully lowering concentration of non-radiative surface recombination centers and reducing leakage current paths. This study provides an attractive platform for micro-LEDs by using sapphire nano-membrane.
在100纳米厚的蓝宝石纳米膜阵列上生长了一种分立的核壳状微发光二极管（micro-LED）阵列，无需进行有害的等离子体蚀刻来进行芯片切割。由于对蓝宝石纳米膜阵列进行了合理设计，生长出了尺寸为4μm×16μm的多面微LED阵列。与在平面衬底上形成的GaN相比，由于蓝宝石纳米膜作为柔性衬底，在蓝宝石纳米膜上形成的微LED中的 threading dislocation density降低了59.6%。还观察到其内部量子效率提高了44%，光致发光强度提高了3.3倍。从c面多量子阱（MQW）测量到435nm处的阴极发光发射，而从半极性侧壁面检测到的发射可忽略不计。在所有面上都形成了核壳状MQW，有望降低非辐射表面复合中心的浓度并减少漏电流路径。这项研究通过使用蓝宝石纳米膜为微LED提供了一个有吸引力的平台。
