کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5431561 | 1508824 | 2017 | 5 صفحه PDF | دانلود رایگان |
The Raman spectra of large-size, single-crystal, twisted bilayer graphene (tBLG) grains grown by chemical vapor deposition (CVD) are measured as a function of the rotation angle. The rotation angle between the graphene layers is determined using a combination of transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The 2D and G peaks follow the same trends as found previously. The low-frequency peaks (<200 cmâ1) are compared to the Î-point modes calculated from large scale molecular dynamics simulations. In this low frequency range, the ZOâ² mode and new Î-point frequencies are observed at angles far from the resonant angle of 12°. The twist-angle dependence of the new modes is not a monotonic function of twist angle or supercell size, and this non-monotonic behavior is consistent with the zone-folded modes determined from the numerical calculations.
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Journal: Carbon - Volume 123, October 2017, Pages 302-306