Shi, Bo; Liu, Zhetong; Li, Yang; Chen, Qi; Liu, Jiaxin; Yang, Kailai; Liang, Meng; Yi, Xiaoyan; Wang, Junxi; Li, Jinmin; Kang, Junjie; Gao, Peng; Liu, Zhiqiang

Source: Nano Letters, 2024; ISSN: 15306984, E-ISSN: 15306992; DOI: 10.1021/acs.nanolett.4c01724; Publisher: American Chemical Society

Articles not published yet, but available online Article in Press

Author affiliation:

Research and Development Center for Solid State Lighting, Institute of Semiconductors, Chinese Academy of Sciences, Beijing; 100083, China

Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing; 100049, China

Electron Microscopy Laboratory, International Center for Quantum Materials, School of Physics, Peking University, Beijing; 100871, China

Abstract:

The majority of dislocations in nitride epilayers are edge threading dislocations (TDs), which diminish the performance of nitride devices. However, it is extremely difficult to reduce the edge TDs due to the lack of available slip systems. Here, we systematically investigate the formation mechanism of edge TDs and find that besides originating at the coalescence boundaries, these dislocations are also closely related to geometrical misfit dislocations at the interface. Based on this understanding, we propose a novel strategy to reduce the edge TD density of the GaN epilayer by nearly 1 order of magnitude via graphene-assisted remote heteroepitaxy. The first-principles calculations confirm that the insertion of graphene dramatically reduces the energy barrier required for interfacial sliding, which promotes a new strain release channel. This work provides a unique approach to directly suppress the formation of edge TDs at the source, thereby facilitating the enhanced performance of photoelectronic and electronic devices.