Catalytic growth of ultralong graphene nanoribbons on insulating substrates

• Main Authors: Lyu, Bosai, Chen, Jiajun, Lou, Shuo, Li, Can, Qiu, Lu, Ouyang, Wengen, Xie, Jingxu, Mitchell, Izaac, Wu, Tongyao, Deng, Aolin, Hu, Cheng, Zhou, Xianliang, Shen, Peiyue, Ma, Saiqun, Wu, Zhenghan, Watanabe, Kenji, Taniguchi, Takashi, Wang, Xiaoqun, Liang, Qi, Jia, Jinfeng, Urbakh, Michael, Hod, Oded, Ding, Feng, Wang, Shiyong, Shi, Zhiwen
• Format: Journal Article
• Language: English
• Published: 27.05.2022
• Subjects: Physics - Materials Science; Physics - Mesoscale and Nanoscale Physics
• DOI: 10.48550/arxiv.2205.13965

Graphene nanoribbons (GNRs) with widths of a few nanometres are promising candidates for future nano-electronic applications due to their structurally tunable bandgaps, ultrahigh carrier mobilities, and exceptional stability. However, the direct growth of micrometre-long GNRs on insulating substrates, which is essential for the fabrication of nano-electronic devices, remains an immense challenge. Here, we report the epitaxial growth of GNRs on an insulating hexagonal boron nitride (h-BN) substrate through nanoparticle-catalysed chemical vapor deposition (CVD). Ultra-narrow GNRs with lengths of up to 10 {\mu}m are synthesized. Remarkably, the as-grown GNRs are crystallographically aligned with the h-BN substrate, forming one-dimensional (1D) moir\'e superlattices. Scanning tunnelling microscopy reveals an average width of 2 nm and a typical bandgap of ~1 eV for similar GNRs grown on conducting graphite substrates. Fully atomistic computational simulations support the experimental results and reveal a competition between the formation of GNRs and carbon nanotubes (CNTs) during the nucleation stage, and van der Waals sliding of the GNRs on the h-BN substrate throughout the growth stage. Our study provides a scalable, single-step method for growing micrometre-long narrow GNRs on insulating substrates, thus opening a route to explore the performance of high-quality GNR devices and the fundamental physics of 1D moir\'e superlattices.