411312 Understanding the Electronic Structures for Different Stacking Modes Bilayer CVD Graphene through Chemical Modification

Tuesday, November 10, 2015: 4:18 PM
251E (Salt Palace Convention Center)
Yao Ding and Zhengtang Luo, Chemical and Biomolecular Engineering, Hong Kong University of Science and Technology, Hong Kong, Hong Kong


Different electronic structures between two identical Chemical Vapor Deposition (CVD) growth stacking modes bilayer graphene (BLG) which are known as AB stacking (Bernal-stacked) and twisted (non-AB stacking or turbostratic-stacked) graphene, are firstly performed by chemical functionalization with diazonium salts. The chemical modification results of two stacking modes graphene with aromatic diazonium ions are analyzed by Raman Spectroscopy. By calculating the ID/IG ratio from Raman spectrum, we find the grafting speed for AB stacking bilayer graphene is much lower than for twisted graphene. We attribute the difference of reaction rates between two stacking modes to the difference of resonance force and the density of states (DOS) between the upper layer and the under layer in this two modes. After D band Raman mapping, the areas of two stacking modes have a significant different shown up rate. Also we find that this reaction speed difference has an edge and bulk area dependence in both two modes BLG. Further TEM, SAED, and XPS test confirm the two stacking modes and the reaction of grafting. This chemical modification by introducing a sp3 defect provides a visible and new way for observing and understanding the DOS and different physical structures between two stacking modes CVD BLG.

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See more of this Session: Composites Technology and Processing II
See more of this Group/Topical: Materials Engineering and Sciences Division