Wafer-Scale High-κ Dielectric for Flexible Electronics Integrated by van der Waals Force.

Two-dimensional semiconductors, particularly atomically thin molybdenum disulfide (MoS), show great promise for flexible electronics due to their exceptional mechanical, electronic, and optical properties. In recent years, MoS has attracted increasing attention, but the direct deposition of high-κ dielectrics on MoS is challenging due to the absence of dangling bonds. In this study, we propose a novel dielectric integration strategy that eliminates the need for stripping and solution assistance. In this approach, dielectrics are predeposited onto a flexible substrate and mechanically pressed onto the MoS surface to create a clean dielectric-semiconductor interface. Additionally, top electrodes and high-κ dielectrics can be predeposited together on the flexible substrate and then transferred to the MoS surface, ensuring high-quality dielectric-semiconductor and dielectric-electrode interfaces. This method enables the formation of perfect interfaces free from damage, folds, or contamination, as the thin film does not require peeling or solution assistance. A capacitance density of 0.55 μF/cm was achieved using a 10 nm AlO dielectric in a metal-insulator-metal device. Our MoS top-gated transistors demonstrated a switching ratio greater than 10 and maintained electrical stability for over 100 cycles. Finally, we successfully fabricated scalable top-gated MoS arrays on a flexible mica substrate, confirming the potential of van der Waals integration in flexible electronics.