1. Twist angle dependent absorption feature induced by interlayer rotations in CVD bilayer graphene
- Author
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Zhou Wen-Guang, Leng Yu-Chen, Liu Li-Xiang, Yang Ming-Ming, Liu Wei, Liu Jing-Lan, Zhao Pei, Liu Yi, Wang Long-Long, Shang Ya-Xuan, Li Xiao-Li, Zhao Xiao-Hui, Liu Xue-Lu, and Xu Yang
- Subjects
bilayer graphene ,optical contrast ,raman spectra ,twist angle ,Physics ,QC1-999 - Abstract
Bilayer graphene (BLG) grown via chemical vapor deposition (CVD) tends to exhibit twisted stacking. The twist angle θ t in twisted BLG (tBLG) provides a new degree of freedom for engineering its electronic and optical properties. In this paper, we investigate the θ t-dependent optical absorption in tBLG and deeply understand the electronic structure-optical properties correlations. New absorption peaks, whose wavelengths are modified by θ t, are observed on the feature of optical contrast (OC) in tBLG. Under the corresponding energy excitation, the Raman G mode in tBLG exhibits a significant enhancement. Furthermore, the results of θ t obtained by OC absorption peak are verified to be consistent with those by the Raman R mode. All these properties are proved to be related to the energy difference between low-energy Van Hove singularities (E VHS) in the density of states of tBLGs. This work builds a relation between optical absorption and twist angle, providing a viable method to identifying twist angles in tBLGs.
- Published
- 2021
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