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

Two-dimensional semiconductors, particularly atomically thin molybdenum disulfide (MoS₂), show great promise for flexible electronics due to their exceptional mechanical, electronic, and optical properties. In recent years, MoS₂ has attracted increasing attention, but the direct deposition of high-κ dielectrics on MoS₂ 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 MoS₂ 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 MoS₂ 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/cm² was achieved using a 10 nm Al₂O₃ dielectric in a metal-insulator-metal device. Our MoS₂ top-gated transistors demonstrated a switching ratio greater than 10⁶ and maintained electrical stability for over 100 cycles. Finally, we successfully fabricated scalable top-gated MoS₂ arrays on a flexible mica substrate, confirming the potential of van der Waals integration in flexible electronics.