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 (Sb 2 O 3 ) fabricated via thermal evaporation deposition. Monolayer molybdenum disulfide (MoS 2 ) field-effect transistors supported by this dielectric substrate exhibit enhanced electron mobility—from 26 cm 2 V −1 s −1 to 145 cm 2 V −1 s −1 —and reduced transfer-curve hysteresis compared with when using SiO 2 substrate. MoS 2 transistors directly gated by the Sb 2 O 3 film can operate with a supply voltage of 0.8 V, on/off ratio of 10 8 and subthreshold swing of 64 mV dec −1 at 300 K.