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

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 approximately 10(6) cm(2) V(-1) s(-1) and the hole mobility approximately 10(4) cm(2) V(-1) s(-1), while for N = 3k + 1 or 3k + 2, the hole mobility is calculated to be 4-8 x 10(5) cm(2) V(-1) s(-1) and the electron mobility approximately 10(4) cm(2) V(-1) s(-1). Such alternating behavior is absent in zigzag-type graphene.