Graphene‐Assisted Epitaxy of Nitrogen Lattice Polarity GaN Films on Non‐Polar Sapphire Substrates for Green Light Emitting Diodes. (29th March 2020)

• Record Type: Journal Article
• Authors: Liu, Fang; Zhang, Zhihong; Rong, Xin; Yu, Ye; Wang, Tao; Sheng, Bowen; Wei, Jiaqi; Zhou, Siyuan; Yang, Xuelin; Xu, Fujun; Qin, Zhixin; Zhang, Yuantao; Liu, Kaihui; Shen, Bo; Wang, Xinqiang
• Is Part Of: Advanced functional materials. Volume 30:Number 22(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-29
• Subjects: graphene -- III‐nitrides -- light emitting diodes -- nitrogen lattice polarity -- nucleation; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202001283
• Languages: English
• ISSNs: 1616-301X

Abstract

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 CN 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. Abstract : A nitrogen‐polarity GaN film has been grown on transferred graphene on a sapphire substrate. This success is achieved through atomic nitrogen irradiation on graphene, which generates CN bonds, leading to nitrogen‐lattice‐polarity and improved quality of the GaN layer. Nitrogen‐polarity green LEDs are successfully fabricated with considerable redshift of emission wavelength, manifesting great potential in long wavelength light‐emitting devices.