AVS 57th International Symposium & Exhibition
    Graphene Focus Topic Tuesday Sessions
       Session GR+TF-TuM

Paper GR+TF-TuM12
Probing the Electronic Structure, Surface Chemistry, and Alignment of Graphene using Soft X-ray Absorption Spectroscopy

Tuesday, October 19, 2010, 11:40 am, Room Brazos

Session: Characterization, Properties, and Applications
Presenter: C. Jaye, NIST
Authors: C. Jaye, NIST
V. Lee, SUNY at Buffalo
P. Lysaght, SEMATECH
S. Banerjee, SUNY at Buffalo
D.A. Fischer, NIST
Correspondent: Click to Email
Graphene, a single layer of graphite packed in a honeycomb lattice, has been the subject of intense scientific research since its discovery in 2004 owing to its remarkable properties such as the half-integer quantum Hall effect, ballistic conduction, and the extremely high mobilities of its charge carriers. Graphene has numerous potential applications in the electronics industry including within ultra-high frequency transistors, electrical interconnects and as a replacement for indium-tin-oxide. Nevertheless, the fabrication of large-area graphene remains a challenge. We present systematic studies of the electronic structure, defect density, and alignment of relatively large-area graphene thin films prepared by a) solution/sonochemical methods and b) chemical vapor deposition (CVD). The solution-chemistry-based approaches have the advantage of ease of scalability, making it an attractive approach for industry. We have been able to achieve the fabrication and transfer of large-area graphene films on both conductive and non-conductive substrates. The fabricated films have been characterized by Raman spectroscopy, near-edge X-ray absorption spectroscopy, and four-point-probe conductivity measurements. This battery of measurements allows evaluation of the role of different reducing agents in reducing graphene oxide to graphene. We have also performed systematic measurements of single-and few-layered graphene grown by CVD onto Cu and Ni substrates. X-ray absorption spectroscopy in particular provides strong evidence for substrate hybridization and rippling of graphene. The ripping of graphene induced during transfer to insulating substrates represents a formidable challenge that will need to be solved since corrugations and electronic asperities in graphene induce local scattering potentials, Finally, we will present some X-ray absorption spectroscopy imaging data showing local electronic asperities in graphene.