Synthesis of Large-Sized van der Waals Layered MoO Single Crystals with Improved Dielectric Performance.

The applications of two-dimensional semiconductors strictly require the reliable integration of ultrathin high-κ dielectric materials on the semiconductor surface to enable fine gate control and low power consumption. As layered oxide materials, MoO can be potentially used as a high-κ two-dimensional material with a larger bandgap and high electron affinity. In this work, relying on the oxidization of molybdenum chlorides, we have synthesized α-MoO single crystals, which can be easily exfoliated into flakes with thicknesses of a few nanometers and sizes of hundreds of micrometers and fine thermal stability. Based on measurement results of conventional metal/insulator/metal devices and graphene based dual-gate devices, the as-received MoO nanosheets exhibit improved dielectric performance, including high dielectric constants and competitive breakdown field strength. Our work demonstrates that MoO with improved crystalline quality is a promising candidate for dielectric materials with a large gate capacitance in future electronics based on two-dimensional materials.