Electronic structure study of ordering and interfacial interaction in graphene/Cu composites

• Published in: Carbon (New York) Vol. 50; no. 14; pp. 5316 - 5322
• Main Authors: Zhang, Liang, Pollak, Elad, Wang, Wei-Cheng, Jiang, Peng, Glans, Per-Anders, Zhang, Yuegang, Cabana, Jordi, Kostecki, Robert, Chang, Chinglin, Salmeron, Miquel, Zhu, Junfa, Guo, Jinghua
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2012; Elsevier
• Subjects: Carbon; CHEMICAL VAPOR DEPOSITION; Chemistry; COMPOSITES; COMPRESSIVE PROPERTIES; Copper; Cross-disciplinary physics: materials science; rheology; ELECTRONIC STRUCTURE; energy storage (including batteries and capacitors), defects, charge transport, materials and chemistry by design, synthesis (novel materials); Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; General and physical chemistry; Graphene; INTERFACES; Materials science; Order disorder; ORDER DISORDER RELATIONSHIPS; Physics; Preserves; PROPERTIES; Specific materials; SPECTRA; Surface physical chemistry; X RAYS; Conduction; Polarization; Shape; Momentum; X-ray absorption; Raman spectroscopy; Substrates; Defects; CVD; Interfaces; Electronic structure; Composite materials; Valence; Energy; Graphene; Graphite; Ordering; X radiation; Charge transfer
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2012.07.020

Graphene CVD-grown on Cu has been studied using Raman spectroscopy, X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES). Raman data indicate the presence of weak compressive strain at the interface of graphene/Cu. Compared with highly ordered pyrolytic graphite (HOPG), new electronic states in the conduction band are observed for graphene/Cu, which are mainly ascribed to the defect states and interfacial interaction between the single graphene layer and Cu surface. Moreover, polarization dependent XAS measurements demonstrate that the graphene/Cu exhibits a high degree of alignment and weak corrugation on the surface. Significant intensity modulation in the resonant XES spectral shape upon different excitation energies near the C K-edge indicates that graphene layer preserves an intrinsic momentum as that of HOPG and the interaction between graphene and Cu shows weak influence on the valence band structure of graphene. However, broad inelastic features and subtle peak shifts are observed in the resonant XES spectra of graphene/Cu in comparison of HOPG, which can be mainly attributed to the electron–phonon scattering and charge transfer from the interfacial interaction of graphene and Cu substrate.