Quantum scattering time and its implications on scattering sources in graphene

Authors

X. Hong, University of Nebraska–LincolnFollow
K. Zou, The Pennsylvania State University
J. Zhu, The Pennsylvania State University

Date of this Version

2009

Document Type

Article

Citation

PHYSICAL REVIEW B 80, 241415(R)

Comments

Used by permission.

Abstract

We determine the quantum scattering time T_q in six graphene samples with mobility of 4 400<μ <17 000 cm² /V s over a wide range of carrier density (1.2<n<6X10¹²/cm2). T_q derived from Shubnikov–de Haas oscillation ranges ~25–74 fs, corresponding to a single-particle level broadening of 4.5–13 meV. The ratio of the transport to quantum scattering time T_t /T_q spans 1.5–5.1 in these samples, which can be quantitatively understood combining scattering from short-ranged centers and charged impurities located within 2 nm of the graphene sheet. Our results suggest that charges residing on the SiO₂ surface play a dominant role in limiting carrier mobility in current samples.