▎ 摘　　要

Graphene based low noise amplifier has been studied actively because the noise characteristics of graphene devices are known to be superior to those of silicon devices. However, 1/f noise characteristics of graphene grown by chemical vapor deposition (CVD) may increase by an order of magnitude when measured before the charge exchange reaction at the interface of the graphene and substrate is saturated. Based on the close correlation between the level of low frequency noise signal and fast charge exchange reaction (in milliseconds), the conductivity fluctuation of graphene caused by the interfacial charge exchange reaction may be the source of the increased low frequency noise. This result suggests that the current assessment of noise characteristics is too optimistic for graphene and that the defect density of CVD graphene needs to be further reduced to minimize the charge exchange reaction. (C) 2012 Elsevier Ltd. All rights reserved.