Controllable Oxidation of ZrS₂ to Prepare High‐κ, Single‐Crystal m‐ZrO₂ for 2D Electronics

Abstract High‐κ materials that exhibit large permittivity and band gaps are needed as gate dielectrics to enhance capacitance and prevent leakage current in downsized technology nodes. Among these, monoclinic ZrO₂ (m‐ZrO₂) shows good potential because of its inertness and high‐κ with respect to SiO₂, but a method to produce ultrathin single crystal is lacking. Here, the controllable preparation of ultrathin m‐ZrO₂ single crystals via the in situ thermal oxidation of ZrS₂ is achieved. As‐grown m‐ZrO₂ presents an equivalent oxide thickness of ≈0.29 nm, a high dielectric constant of ≈19, and a breakdown voltage (E_BD) of ≈7.22 MV cm⁻¹. MoS₂ field effect transistor (FET) by using m‐ZrO₂ as a dielectric layer shows comparable mobility to that using SiO₂ dielectric. The ultraclean interface of m‐ZrO₂/MoS₂ and high crystalline quality of m‐ZrO₂ lead to negligible hysteresis in transfer curves. Single crystal m‐ZrO₂ dielectric shows potential application in digital complementary metal oxidesemiconductor (CMOS) logic FET.