Thinner 2D α-MoO3 makes setting up memristors easier

Two-dimensional (2D) metal oxide α-MoO3 shows great potentials because of its very high dielectric constant, air stability and anisotropic phonon polaritons. However, a method to produce ultrathin single crystalline α-MoO3 with high transferability for functional device architecture is lacking. Herein, we report on the controllable synthesis of ultrathin α-MoO3 single crystals via chemical vapor deposition (CVD) assisted by plasma pretreatment. We also carried out systematic computational work to explicate the mechanism for the slantly-oriented growth of thin nanosheets on plasma-pretreated substrate. The method possesses certain universality to synthesize other ultrathin oxide materials, such as Bi2O3 and Sb2O3 nanosheets. As-grown α-MoO3 presents a high dielectric constant (≈40), ultrathin thickness (≈3 nm) and high transferability. Memristors with α-MoO3 as the functional layers show excellent performance featuring high on/off ratio of approximately 104, much lower set voltage around 0.5 V, and highly repetitive voltage sweep endurance. The power consumption of MoO3 memristors is significantly reduced, resulted from reduced thickness of the MoO3 nanosheets. Single crystal ultrathin α-MoO3 shows great potentials in post-Moore memristor and the synthesis of CVD assisted by plasma pretreatment approach points to a new route for materials growth.