Strong mobility degradation in ideal graphene nanoribbons due to phonon scattering

We investigate the low-field phonon-limited mobility in armchair graphene nanoribbons (GNRs) using full-band electron and phonon dispersion relations. We show that lateral confinement suppresses the intrinsic mobility of GNRs to values typical of common bulk semiconductors, and very far from the impressive experiments on two-dimensional graphene. 1 nm-wide suspended GNRs exhibit a mobility close to 500 cm2/V s at room temperature, whereas 1 nm-wide GNRs deposited on HfO2 exhibit a mobility of 60 cm2/V s due to surface phonons. We also show the occurrence of polaron formation, leading to band gap renormalization of ≈118 meV for 1-nm-wide armchair GNRs.