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.