Graphene‐Assisted Epitaxy of Nitrogen Lattice Polarity GaN Films on Non‐Polar Sapphire Substrates for Green Light Emitting Diodes
作者：Fang Liu, Zhihong Zhang, Xin Rong, Ye Yu, Tao Wang, Bowen Sheng, Jiaqi Wei, Siyuan Zhou, Xuelin Yang, Fujun Xu, Zhixin Qin, Yuantao Zhang, Kaihui Liu, Bo Shen, Xinqiang Wang · 发表于：Advanced Functional Materials · 年份：2020 · DOI：10.1002/adfm.202001283 · 被引用次数：54 · 研究领域：GaN-based semiconductor devices and materials、Ga2O3 and related materials、ZnO doping and properties
Abstract Lattice polarity is a key point for hexagonal semiconductors such as GaN. Unfortunately, only Ga‐polarity GaN have been achieved on graphene till now. Here, the epitaxy of high quality nitrogen‐polarity GaN films on transferred graphene on non‐polar sapphire substrates by molecular beam epitaxy is reported. This success is achieved through atomic nitrogen irradiation, where CN bonds are formed in graphene and provide nucleation sites for GaN and leading to N‐polarity GaN epitaxy. The N‐polarity characteristics are confirmed by chemical etching and transmission electron microscopy measurement. Due to the higher growth temperature of InGaN at N‐polarity than that at Ga‐polarity, green light emitting diodes are fabricated on the graphene‐assisted substrate, where a large redshift of emission wavelength is observed. These results open a new avenue for the polarity modulation of III‐nitride films based on 2D materials, and also pave the way for potential application in longer wavelength light emitting devices.