Deep-ultraviolet Raman scattering studies of monolayer graphene thin films

• Published in: Carbon (New York) Vol. 81; pp. 807 - 813
• Main Authors: Liu, Hsiang-Lin, Siregar, Syahril, Hasdeo, Eddwi H., Kumamoto, Yasuaki, Shen, Chih-Chiang, Cheng, Chia-Chin, Li, Lain-Jong, Saito, Riichiro, Kawata, Satoshi
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.01.2015; Elsevier
• Subjects: Carbon; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Excitation; Fullerenes and related materials; Fullerenes and related materials; diamonds, graphite; Graphene; Infrared and raman spectra and scattering; Materials science; Monolayers; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photons; Physics; Raman scattering; Specific materials; Spectra; Thin films; Thin films; Ultrathin films; Raman spectra; Raman scattering; Graphene; Monolayers; Ultraviolet spectra
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2014.10.028

We present joint experimental and theoretical investigations of the deep-ultraviolet Raman scattering spectra of monolayer graphene thin films. We found that upon a 266nm laser excitation, while the G mode remains pronounced, the G′ mode is not observed. The G′ mode exhibits distinctive linewidth broadening towards the ultraviolet frequency region. The peak intensity ratio of the G′ and G modes increases dramatically excited at 355, 532, and 785nm wavelengths. All of the experimental findings are in good agreement with the theory calculated by the tight-binding method. We theoretically show that the integrated intensity of the G′ mode is inversely proportional to the incident photon energy, whereas that of the G mode increases as the fourth power of the incident photon energy. These results extend our understanding of the double resonance Raman scattering process of graphene away from the Dirac cones and provide the foundation for future technologically important developments of graphene in the deep-ultraviolet frequency range.