Effect of current annealing to the transport properties of CVD graphene cooled with a biased gate voltage*

Chemical vapor deposition of graphene is an excellent method for obtaining large area single-layer graphene. A topic of interest in this area is to characterize and reduce the impurity level in this material. In this experimental work, we investigate impurity effects on electron /hole transport in a graphene specimen by cooling down a graphene Hall bar device under different gate bias voltages. Further, we examine the impact of current annealing on the transport characteristics. Here we present results from the measurements carried out in a closed cycle refrigerator out over a broad temperature range (295K–15K), focusing on the charge neutrality point.