Author(s): Liu, Y (Liu, Yi); Shi, YF (Shi, Yafang); Zhou, WG (Zhou, Wenguang); Shi, W (Shi, Wei); Dang, W (Dang, Wei); Li, XL (Li, Xiaoli); Liang, BL (Liang, Baolai)

Source: OPTICS AND LASER TECHNOLOGY Volume: 139 Article Number: 106960 DOI: 10.1016/j.optlastec.2021.106960 Published: JUL 2021

Abstract: Dedicated Raman spectroscopy investigations in the temperature range from 78 K to 298 K were performed for the graphene suspended above round holes on SiO2/Si substrate (the suspended graphene, SUG), in comparison with the surrounding graphene adhered to solid SiO2/Si substrate (the substrate supported graphene, SSG). The results confirmed that one-layer SUG (1L-SUG) was subjected to strains originated from the surrounding 1L-SSG due to the different area and shape around the hole along different directions. In further, the split-up of G band and 2D band were observed at low temperature because of the enhanced anisotropic strains in 1L-SUG due to the mismatch of thermal expansion coefficient (TEC) between the 1L-SSG and SiO2/Si substrates. The temperature dependent (T-dependent) frequency shifts for the G band and 2D band in 1L-SUG and 1L-SSG were consistent with previous Raman investigations. Therefore, the micro-hole boundary effect in suspended graphene play a significant role in determination of the properties for graphene materials and graphene-based flexible devices.

Accession Number: WOS:000632368000006

ISSN: 0030-3992

eISSN: 1879-2545

Full Text: https://www.sciencedirect.com/science/article/pii/S0030399221000487?via%3Dihub