title: Current crowding mediated large contact noise in graphene field-effect transistors.
abstract: The impact of the intrinsic time-dependent fluctuations in the electrical resistance at the graphene-metal interface or the contact noise, on the performance of graphene field-effect transistors, can be as adverse as the contact resistance itself, but remains largely unexplored. Here we have investigated the contact noise in graphene field-effect transistors of varying device geometry and contact configuration, with carrier mobility ranging from 5,000 to 80,000 cm2V-1s-1. Our phenomenological model for contact noise because of current crowding in purely two-dimensional conductors confirms that the contacts dominate the measured resistance noise in all graphene field-effect transistors in the two-probe or invasive four-probe configurations, and surprisingly, also in nearly noninvasive four-probe (Hall bar) configuration in the high-mobility devices. The microscopic origin of contact noise is directly linked to the fluctuating electrostatic environment of the metal-channel interface, which could be generic to two-dimensional material-based electronic devices.
authors.affiliation: Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: Paritosh
authors.initials: P
authors.lastname: Karnatak
authors.affiliation: Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: T Phanindra
authors.initials: TP
authors.lastname: Sai
authors.affiliation: Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: Srijit
authors.initials: S
authors.lastname: Goswami
authors.affiliation: Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: Subhamoy
authors.initials: S
authors.lastname: Ghatak
authors.affiliation: Tokyo Electron Ltd, Akasaka Biz Tower, 3-1 Akasaka 5-Chome, Minato-ku, Tokyo 107-6325, Japan.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Kaushal
authors.affiliation: Department of Physics, Indian Institute of Science, Bangalore 560 012, India.|Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: Arindam
authors.initials: A
authors.lastname: Ghosh