Large-area two-dimensional MoO3 as a high-κ dielectric for van der Waals integration.

Large-area high-quality dielectrics are essential for the integration of two-dimensional (2D) transistors. However, this integration remains challenging, especially for conventional dielectrics that require deposition processes. Adopting van der Waals (vdW) dielectrics is attractive. Molybdenum trioxide (α-MoO3) has been demonstrated as a vdW dielectric in 2D field-effect transistors (FETs), but previous demonstrations showed limited performance and small size. Here, we grow large-area single-crystalline MoO3 with uniform thickness and explore its properties as a dielectric. Single-crystalline MoO3 reaches the millimeter scale and maintains a high dielectric constant of ~ 18.5, low gate leakage of approximately 10-2 A cm-2 at 3.0 MV cm-1, and a large breakdown field of ~ 26.75 MV cm-1. Top-gated molybdenum disulfide (MoS2) transistors exhibit an average subthreshold swing of ~ 71 mV dec-1, and an on/off current ratio exceeding 108. Furthermore, we demonstrate MoO3-based integrated circuits and low-power complementary metal-oxide-semiconductor (CMOS) inverters.