title: The impact of Cr adhesion layer on CNFET electrical characteristics.
abstract: The effect of a Cr adhesion layer on the transfer characteristics of Cr/Au-contacted carbon nanotube field-effect transistors (CNFETs) based on individual single-walled carbon nanotubes (SWNTs) is presented in this paper. We show that a very thin Cr layer (≈0.4 nm) already has an impact on the carrier transport in Schottky-barrier-modulated CNFETs. The ratio of the p- and n-branch current is reduced by eight times when the Cr adhesion layer thickness is increased from 0 to 8 nm. We suggest a change in Schottky barrier height at the contact as the determining mechanism for this result. Additionally, superior lifetime of devices is observed even for non-passivated CNFETs with preserved clean SWNT/Cr/Au-contacts using Cr layer thinner than 2 nm. Our experiments show that the role of the adhesion layer in metal/nanotube contacts should be explicitly considered when designing CNTFET-based circuits, developing CNFET fabrication processes, and analyzing the corresponding properties of the electrical contacts.
authors.affiliation: Micro and Nanosystems, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Kiran
authors.initials: K
authors.lastname: Chikkadi
authors.forename: Matthias
authors.initials: M
authors.lastname: Muoth
authors.forename: Christofer
authors.initials: C
authors.lastname: Hierold
authors.forename: Miroslav
authors.initials: M
authors.lastname: Haluska