Wafer-scale van der Waals Dielectrics of Inorganic Molecular Crystals

Abstract

Van der Waals (vdW) dielectrics such as hBN are widely used to preserve the intrinsic properties of two-dimensional (2D) semiconductors and support the fabrication of high-performance 2D devices. This is fundamentally attributed to their dangling-bond-free surface, carrying far lower density of charged scattering sources and trap states with respect to the conventional dielectrics (SiO2 etc.). However, their wafer-scale fabrication and compatible integration with 2D semiconductors remain cumbersome, giving rise to the difficulties in scalable fabrication of high-performance 2D devices. Here we report a high-κ vdW dielectric (εr=11.5) composed of inorganic molecular crystal (IMC) Sb2O3, allowing for large-scale fabrication and facile integration via standard thermal evaporation process thanks to its particular crystal structure. Similarly, our vdW dielectric also supports remarkably improved 2D devices with respect to the typical conventional dielectric SiO2. The monolayer MoS2 field effect transistors (FET) supported by our vdW dielectric exhibits high on/off ratio (108), greatly enhanced electron mobility (from 20 to 80 cm2/Vs) and reduced transfer-curve hysteresis over an order of magnitude. Our results may open a new avenue towards compatible fabrication of vdW dielectrics using IMCs and lead to the scalable fabrication of high-performance 2D devices.