Charging and discharging of graphene in ambient conditions studied with scanning probe microscopy

Abstract

4 páginas, 3 figuras.-- Trabajo presentado como comunicación oral a la "European Conference on Surface Science ECOSS27" celbrado en Holanda en septiembre de 2010: http://www.ecoss27.eu/By means of scanning probe microscopy we are able to inject charges in isolated graphene sheets deposited on SiO2/Si wafers and characterize the discharge induced by water in controlled ambient conditions. Contact potential differences between the graphene surface and the probe tip, measured by Kelvin probe microscopy, show a linear relationship with the tip bias during charge injection. The discharge depends on relative humidity and decays exponentially with time constants of the order of tens of minutes. We propose that graphene discharges through the water film adsorbed on the SiO2 surface.This work was supported by the Ministerio de Educación y Ciencia (MEC), Spain, through Grant No. FIS2006-12117- C04-01, and by the EXPLORA program NAN2007-29375-E.Peer reviewe