Negative magnetoresistance in Ti-cleaned single-layer graphene. (March 2015)

• Record Type: Journal Article
• Authors: Fujimoto, A; Joiner, C A; Jiang, Y; Terasawa, D; Fukuda, A; Jiang, Z; Vogel, E M
• Is Part Of: Journal of physics. Number 603(2015)
• Publication Date: 2015-03
• Subjects: Physics -- Congresses; 530.5
• DOI: 10.1088/1742-6596/603/1/012021
• Languages: English
• ISSNs: 1742-6588

Abstract

Abstract: Symmetric graphene tunnelingfield-effect transistors (SymFETs) consisting of two independently gated graphene layers separated by a potential barrier have been proposed as a room-temperature resonant tunneling device. In a SymFET, the inelastic-coherent length ( L ϕ ) of the electrons is considered to be one of the important characteristic scattering lengths. Weak localization (WL) is a good tool to estimate L ϕ In this study, the surface of the chemical-vapor- deposited single-layer graphene was Ticleaned after performing the conventional fabrication processes for graphene transistors. We found that the charge-neutral point ( V CNP ) shifted to a lower back-gate voltage and the mobility increased owing to Ticleaning. Ti-cleaned Hall bars were investigated at 0.3 K under magnetic fields of up to 14 T. Negative magnetoresistance(MR) appears because of the WL effect, and the MR increases as the back-gate voltage ( V G ) approaches V CNP . From a fitting analysis using the theoretical formulation of WL, we found that L ϕ was greater than 100 nm and that L ϕ decreased as V G approached V CNP because of electron-hole puddles and electron-electron interaction.