Ultralow-contact-resistance graphene field-effect transistors fabricated with P-type solution doping

We developed a polymer-free (PF) transfer method and examined the optimum annealing temperature and time for the polymer-free graphene to improve the graphene-metal contact. To further tune the work function of graphene to reduce contact resistance, we report solution doping combined with the PF method, and by using P-doped graphene, the contact resistance is markedly reduced to 24 ? µm, which is an extremely low value in recent research. Photoemission spectroscopy was used to investigate the graphene/Au interface to explain the results of our contact resistance measurements, and the highest FET mobility of these low-contact devices was 14400 cm2V?1s?1for intrinsic graphene in this study.