Theoretical Predictions of Size-Dependent Carrier Mobility and Polarity in Graphene

(Figure Presented) First-principles density functional theory coupled with deformation potential calculations indicate a strong width-dependent carrier mobility: for an armchair graphene ribbon whose width (i.e., number of carbons along the edge) is N = 3k, the room-temperature electron mobility is calculated to be ∼106 cm2 V-1 s-1 and the hole mobility ∼104 cm2 V-1 s-1, while for N = 3k + 1 or 3k + 2, the hole mobility is calculated to be 4-8 x 105 cm2 V-1 s-1 and the electron mobility ∼104 cm2 V-1 s-1. Such alternating behavior is absent in zigzag-type graphene. © 2009 American Chemical Society.