Centimetre-scale single crystal α-MoO3: oxygen assisted self-standing growth and low-energy consumption synaptic devices

Abstract

High-density storage and neuromorphic devices based on 2D materials are hindered by large-scale growth. Moreover, the lack of a mature mechanism makes it difficult to obtain high-quality single crystals in large-scale 2D materials. In this work, we prepared a centimeter-scale single crystal α-MoO₃via an oxygen assisted substrate-free self-standing growth method and mechanism and constructed high-performance synaptic devices based on the centimeter-scale α-MoO₃. The oxygen assisted growth mechanism of α-MoO₃ was developed from the periodic bond chain theory. The large-scale α-MoO₃ is up to 2 cm and exhibits high homogeneity and single crystalline characteristic. Furthermore, with an optimized oxygen partial pressure (18%), the centimeter-scale α-MoO₃ makes the as-prepared memristor achieve continuous conductance modulation. Moreover, the trap-controlled electron conducting mechanism of the memristor was demonstrated through I–V curve fitting analysis at various temperatures, in which the high resistance state section demonstrates space-charge-limited conduction (SCLC) mode. Moreover, the as-prepared α-MoO₃ memristors exhibit low-energy consumption and well emulate the essential synaptic behaviors including excitatory/inhibitory postsynaptic current, paired-pulse facilitation and long-term plasticity.