Submillimeter‐Sized Neodymium Oxychloride Single‐Crystal Dielectrics for 2D Electronics

Abstract 2D dielectrics integrated with atomically thin semiconductors hold immense potential to address the scaling challenges in future nanoelectronics. However, existing 2D dielectrics are limited by insufficient dielectric constants, poor interfacial quality, and degraded gate controllability. Here, a controlled synthesis of single‐crystal neodymium oxychloride (NdOCl) nanosheets with submillimeter sizes (169 µm) and ultrathin thickness (5 nm) is presented using a modified physical vapor deposition (PVD) approach. The NdOCl nanosheets exhibit a high dielectric constant (κ≈11.7), ultralow leakage currents (≈10 −7 A cm −2 ), and a wide bandgap of 4.57 eV. MoS 2 /NdOCl field‐effect transistors (FETs) achieve high on/off current ratios (10 8 ), steep subthreshold swings, and suppressed Coulomb scattering, enabling a carrier mobility of 123 cm 2 V −1 s −1 at 80 K, a value three times higher than MoS 2 /SiO 2 FETs. The implementation of high‐κ NdOCl dielectrics facilitates the successful fabrication of short‐channel MoS 2 FETs (100 nm) and high‐gain logic inverters (60.9). These findings underscore the great potential of NdOCl as a next‐generation 2D gate dielectric for advanced, miniaturized nanoelectronic applications.