▎ 摘　　要

The gas sensing behavior of a metal-graphene contact is investigated by transfer length method (TLM). By simultaneously measuring the resistance of all channels in a TLM device, the time evolution of the metal-graphene contact resistance and the graphene sheet resistance are obtained. When the device is exposed to 10 ppm ammonia, the response time of the nickel-graphene contact resistance is only one-third of the pure sheet resistance, and the sensitivity of the contact resistance is about 180% and that of the graphene sheet resistance is 100%. The results of this work indicate that the contact resistance can be an effective gas sensing parameter. Published by AIP Publishing.