We have investigated the effect of Au-ion treatment on the work function and the electronic structure change of reduced graphite oxides (RGOs). Au-ions were reduced spontaneously by extracting electrons (i) from sp(2) carbons of RGO at low concentration and (ii) from some oxygen-related functional groups at high concentration. This implies that the work function was modulated by the amount of charges transferred to Au-ions. The sheet resistance of the RGO film was improved with Au-ion treatment. This was explained in terms of electron donation to Au-ions that eventually led to a p-type doping in RGO film. (c) 2009 Elsevier B.V. All rights reserved.