Extremely High Intrinsic Carrier Mobility and Quantum Hall Effect Of Single Crystalline Graphene Grown on Ge(110)

The successful synthesis of wafer-scale single crystalline graphene on semiconducting Ge substrate has been considered a significant breakthrough toward the manufacturing of graphene-based electronic and photonic devices; however, the assumed extremely high electrical mobility has not been found yet due to the lack of an adequate characterization method. Herein, state-of-the-art transfer methods are developed to encapsulate the single crystalline graphene, which is grown on semiconducting Ge(110), in two hexagonal boron nitride (hBN) flakes, then acquire its inherent electrical mobility precisely via edge-contact technique. It is found that single crystalline graphene grown on Ge(110) possesses a maximum carrier mobility of over 100 000 cm² V⁻¹ s⁻¹ at low temperatures (2.3 K), which is superior to that obtained from graphene grown on other nonmetal substrates. Due to the extremely high mobility, well-defined quantum Hall effect and Shubnikov-de Haas oscillations can be observed at low temperatures as well. The study suggests that the excellent carrier mobility of graphene grown on Ge(110) may open an avenue to develop the practical graphene-based nanodevices with high performance. © 2023 The Authors. Advanced Materials Interfaces published by Wiley-VCH GmbH.