Synchronous growth of 30^◦-twisted bilayer graphene domains with millimeter scale

Bilayer graphene (BLG) with 30^◦-twist (30^◦-tBLG) has been proven to possess a quasicrystal structure potentially providing novel applications. Despite the growth of BLG, especially the AB-stacking bilayer, has gained great attention, the growth of 30^◦-tBLG has been rarely achieved. Herein, for the first time, the decaborane-assisted synchronous growth of millimeter-sized single-crystalline 30^◦-tBLG was achieved on Cu foil by controlling the nucleation density and growth kinetics of graphene during chemical vapor deposition using diluted methane gas as the carbon source. The synchronous growth kinetics and decaborane-assisted co-catalysis mechanism are revealed by monitoring the growth process from the initial stage of graphene seeds to the millimeter-size scale. A 30^◦-tBLG based field effect transistor was fabricated and was found to possess a field-effect carrier mobility as high as 3671.3 cm² V⁻¹ s⁻¹ at room temperature. Thus, this work provides a new strategy to grow high-quality and large-scale 30^◦-tBLG domains which will facilitate their application in the quasicrystal field.