▎ 摘　　要

A highly electrically tunable gas sensing performance of graphene-metal contact resistance is reported here. The response of graphene-nickel contact resistance (R-C) is improved from 16% to 87% by switching the back-gate voltage (V-BG) from 0 to 30 V during an ammonia gas sensing test. More importantly, the transfer characteristics of R-C display a highly nonlinear performance when the channel is bias close to its charge neutron point. As a result, diverse of gas sensing behavior is observed at various V-BG, 30, 40 and 50 V for instance. The results of this work indicate that the gas sensing performance of graphene-metal contact can be significantly improved via applying a proper back-gate voltage. A highly tunable gas sensing behavior may enrich the device design strategy especially towards gas sensor arrays. (C) 2020 Elsevier B.V. All rights reserved.