Dielectric-assisted transfer using single-crystal antimony oxide for two-dimensional material devices

Abstract

Two-dimensional (2D) materials could be used to build next-generation electronics. However, despite progress in the synthesis of single-crystal 2D wafers for use as the channel material in devices, the preparation of single-crystal dielectric wafers—and their reliable integrating on 2D semiconductors with clean interfaces, large gate capacitance and low leakage current—remains challenging. Here we show that thin (around 2 nm) single-crystal wafers of the dielectric antimony oxide (Sb₂O₃) can be epitaxially grown on a graphene-covered copper surface. The films exhibit good gate controllability at an equivalent oxide thickness of 0.6 nm. The conformal growth of Sb₂O₃ allows graphene to be transferred onto application-specific substrates with a low density of cracks and wrinkles. With the approach, and due to the clean dielectric interface, graphene devices can be fabricated on a four-inch wafer that exhibit a maximum carrier mobility of 29,000 cm² V⁻¹ s⁻¹ (average of 14,000 cm² V⁻¹ s⁻¹) and good long-term stability. The Sb₂O₃ can also be transferred and used as a dielectric in molybdenum disulfide (MoS₂) devices, leading to devices with an on/off ratio of 10⁸ and minimum subthreshold swing of 64 mV dec⁻¹.