▎ 摘　　要

The contact resistance of metals on backgated graphene field-effect transistors is studied. The residual resistance obtained at high backgate voltage is found to be in excellent agreement with the extracted values of contact resistance from transfer length measurements on graphene flakes. The contact resistance is found to be a significant contributor to the total resistance of graphene-based devices. The specific contact resistance is shown to be independent of the applied backgate voltage and the number of graphene layers.