High-κ monocrystalline dielectrics for low-power two-dimensional electronics

The downscaling of complementary metal-oxide-semiconductor technology has produced breakthroughs in electronics, but more extreme scaling has hit a wall of device performance degradation. One key challenge is the development of insulators with high dielectric constant, wide bandgap and high tunnel masses. Here, we show that two-dimensional monocrystalline gadolinium pentoxide, which is devised through combining particle swarm optimization algorithm and theoretical calculations and synthesized via van der Waals epitaxy, could exhibit a high dielectric constant of ~25.5 and a wide bandgap simultaneously. A desirable equivalent oxide thickness down to 1 nm with an ultralow leakage current of ~10^-4 A cm^-2 even at 5 MV cm^-1 is achieved. The molybdenum disulfide transistors gated by gadolinium pentoxide exhibit high on/off ratios over 10⁸ and near-Boltzmann-limit subthreshold swing at an operation voltage of 0.5 V. We also constructed inverter circuits with high gain and nanowatt power consumption. This reliable approach to integrating ultrathin monocrystalline insulators paves the way to future nanoelectronics.