Exceptional Thermochemical Stability of Graphene on N-Polar GaN for Remote Epitaxy

Joonghoon Choi, Junseok Jeong, Xiangyu Zhu, Junghwan Kim, Bong Kyun Kang, Qingxiao Wang, Bo In Park, Seokje Lee, Jekyung Kim, Hyunseok Kim, Jinkyoung Yoo, Gyu Chul Yi, Dong Seon Lee, Jeehwan Kim, Suklyun Hong, Moon J. Kim, Young Joon Hong

Research output: Contribution to journalArticlepeer-review


In this study, we investigate the thermochemical stability of graphene on the GaN substrate for metal-organic chemical vapor deposition (MOCVD)-based remote epitaxy. Despite excellent physical properties of GaN, making it a compelling choice for high-performance electronic and light-emitting device applications, the challenge of thermochemical decomposition of graphene on a GaN substrate at high temperatures has obstructed the achievement of remote homoepitaxy via MOCVD. Our research uncovers an unexpected stability of graphene on N-polar GaN, thereby enabling the MOCVD-based remote homoepitaxy of N-polar GaN. Our comparative analysis of N- and Ga-polar GaN substrates reveals markedly different outcomes: while a graphene/N-polar GaN substrate produces releasable microcrystals (μCs), a graphene/Ga-polar GaN substrate yields nonreleasable thin films. We attribute this discrepancy to the polarity-dependent thermochemical stability of graphene on the GaN substrate and its subsequent reaction with hydrogen. Evidence obtained from Raman spectroscopy, electron microscopic analyses, and overlayer delamination points to a pronounced thermochemical stability of graphene on N-polar GaN during MOCVD-based remote homoepitaxy. Molecular dynamics simulations, corroborated by experimental data, further substantiate that the thermochemical stability of graphene is reliant on the polarity of GaN, due to different reactions with hydrogen at high temperatures. Based on the N-polar remote homoepitaxy of μCs, the practical application of our findings was demonstrated in fabrication of flexible light-emitting diodes composed of p-n junction μCs with InGaN heterostructures.

Original languageEnglish (US)
Pages (from-to)21678-21689
Number of pages12
JournalACS Nano
Issue number21
StatePublished - Nov 14 2023
Externally publishedYes


  • deformable light-emitting diode
  • N-polar GaN
  • polarity
  • remote epitaxy
  • thermochemical stability

ASJC Scopus subject areas

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy


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