Twist angle-dependent transport properties of twisted bilayer graphene

Abstract

Twisted bilayer graphene (tBLG) with small twist angles has attracted significant attention because of its unique electronic properties arising from the formation of a moiré superlattice. In this study, we systematically characterized the twist-angle-dependent electronic and transport properties of tBLG grown via chemical vapor deposition. This characterization included parameters such as the charge-neutral point voltage, carrier concentration, resistance, and mobility, covering a wide range of twist angles from 0° to 30°. We experimentally demonstrated that these parameters exhibited twist-angle-dependent moiré period trends, with high twist angles exceeding 9°, revealing more practically useful features, including improved mobilities compared to those of single-layer graphene. In addition, we demonstrated that the doping states and work functions were weakly dependent on the twist angles, as confirmed by additional first-principles calculations. This study provides valuable insights into the transport properties of tBLG and its potential for practical applications in the emerging field of twistronics.