A wafer-scale van der Waals dielectric made from an inorganic molecular crystal film

Van der Waals dielectrics, such as hexagonal boron nitride, are widely used to preserve the intrinsic properties of two-dimensional semiconductors in electronic devices. However, fabricating these materials on the wafer scale and integrating them with two-dimensional semiconductors is challenging because their synthesis typically requires mechanical exfoliation or vapour deposition processes. Here we show that a high-κ van der Waals dielectric can be created on wafer scales using an inorganic molecular crystal film of antimony trioxide (Sb2O3) fabricated via thermal evaporation deposition. Monolayer molybdenum disulfide (MoS2) field-effect transistors supported by this dielectric substrate exhibit enhanced electron mobility—from 26 cm2 V−1 s−1 to 145 cm2 V−1 s−1—and reduced transfer-curve hysteresis compared with when using SiO2 substrate. MoS2 transistors directly gated by the Sb2O3 film can operate with a supply voltage of 0.8 V, on/off ratio of 108 and subthreshold swing of 64 mV dec−1 at 300 K. Inorganic molecular crystal films of antimony trioxide can be fabricated using thermal evaporation deposition and used as a van der Waals dielectric in molybdenum disulfide field-effect transistors.