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

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 (EBD) 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. The controllable preparation of ultrathin monoclinic ZrO2 (m‐ZrO2) single crystals (EOT≈0.29 nm, EOT is equivalent oxide thickness) via thermal oxidation of ZrS2 is achieved. By using K3[Fe(CN)6] as seeding, the large‐scale parent ZrS2 is easily grown. The grown m‐ZrO2 presents a high dielectric constant of ≈19 and a breakdown voltage of ≈7.22 MV cm−1. Using m‐ZrO2 as top gate dielectric, the MoS2 field effect transistor (FET) shows excellent device performance.