Single-crystalline High-κ GdOCl dielectric for two-dimensional field-effect transistors

Two-dimensional (2D) dielectrics, integrated with high-mobility semiconductors, show great promise to overcome the scaling limits in miniaturized integrated circuits. However, the 2D dielectrics explored to date still face the challenges of low crystallinity, diminished dielectric constant, and the lack of effective synthesis methods. Here, we report the controllable synthesis of ultra-thin gadolinium oxychloride (GdOCl) nanosheets via a chloride hydrate-assisted chemical vapor deposition (CVD) method. The resultant GdOCl nanosheets display good dielectric properties, including a high dielectric constant (high-κ) of 15.3, robust breakdown field strengths (Ebd) exceeding 9.9 MV/cm, and minimal gate leakage currents of approximately 10−6 A/cm2. The top-gated GdOCl/MoS2 field-effect transistors (FETs) exhibit commendable switch characteristics, a negligible hysteresis of ~5 mV and a subthreshold swing down to 67.9 mV dec−1. The GdOCl/MoS2 FETs can also be employed to construct functional logic gates. Our study underscores the significant potential of the 2D GdOCl dielectric for innovative high-speed operated nanoelectronic devices. van der Waals dielectric materials are required to promote the industrialization of miniaturized 2D electronics. Here, the authors report the growth of GdOCl single crystals with a dielectric constant of 15.3 and equivalent oxide thickness down to 1.3 nm, showing their application for the realization of high-performance 2D MoS2 transistors.