▎ 摘　　要

Photoluminescence (PL) and Raman studies have been performed to investigate the optical properties of graphene thin films prepared by chemical and thermal reductions of graphene oxide (GO). The G peak in Raman spectra red-shifted after reduction of GO. Thermal reduction resulted in a more red-shift of the G peak than chemical reduction. A strong intensity of the D peak indicated that the prepared graphene films have significant structural disorders. A blue-shifted emission in PL spectra suggested that sp(2) clusters are embedded in a sp(3) matrix that acts as a tunnel barrier, causing a strong fluctuation in the local band gap. (C) 2009 Elsevier B.V. All rights reserved.