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arXiv · 2402.04778

Suppression of nucleation density in twisted graphene domains grown on graphene/SiC template by sequential thermal process

Yao Yao·Taiki Inoue·Makoto Takamura·Yoshitaka Taniyasu·Yoshihiro Kobayashi
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Abstract

We investigated the growth of twisted graphene on graphene/silicon carbide (SiC-G) templates by metal-free chemical vapor deposition (CVD) through a sequential thermal (ST) process, which exploits the ultraclean surface of SiC-G without exposing the surface to air before CVD. By conducting control experiments with SiC-G templates exposed to air (AirE process), structural analysis by atomic force microscopy revealed that the nucleation density of CVD graphene (CVD-G) was significantly suppressed in the ST process under the same growth condition. The nucleation behavior on SiC-G surfaces is observed to be very sensitive to carbon source concentration and process temperature. The nucleation on the ultraclean surface of SiC-G prepared by the ST process requires higher partial pressure of carbon source compared with that on the surface by the AirE process. Moreover, analysis of CVD-G growth over a wide temperature range indicates that nucleation phenomena change dramatically with a threshold temperature of 1300°C, possibly due to arising of etching effects. The successful synthesis of twisted few-layer graphene (tFLG) was affirmed by Raman spectroscopy, in which analysis of the G' band proves a high ratio of twisted structure in CVD-G. These results demonstrate that metal-free CVD utilizing ultraclean templates is an effective approach for the scalable production of large-domain tFLG that is valuable for electronic applications.

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Yao Yao, Taiki Inoue, Makoto Takamura, Yoshitaka Taniyasu, Yoshihiro Kobayashi. 2024-02-07. Suppression of nucleation density in twisted graphene domains grown on graphene/SiC template by sequential thermal process. https://doi.org/10.1021/acs.cgd.3c01331

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