Facile Hydrothermal Synthesis and Resistive Switching Mechanism of the α-Fe₂O₃ Memristor

Among the transition metal oxides, hematite (α-Fe₂O₃) has been widely used in the preparation of memristors because of its excellent physical and chemical properties. In this paper, α-Fe₂O₃ nanowire arrays with a preferred orientation along the [110] direction were prepared by a facile hydrothermal method and annealing treatment on the FTO substrate, and then α-Fe₂O₃ nanowire array-based Au/α-Fe₂O₃/FTO memristors were obtained by plating the Au electrodes on the as-prepared α-Fe₂O₃ nanowire arrays. The as-prepared α-Fe₂O₃ nanowire array-based Au/α-Fe₂O₃/FTO memristors have demonstrated stable nonvolatile bipolar resistive switching behaviors with a high resistive switching ratio of about two orders of magnitude, good resistance retention (up to 10³ s), and ultralow set voltage (V_set = +2.63 V) and reset voltage (V_reset = -2 V). In addition, the space charge-limited conduction (SCLC) mechanism has been proposed to be in the high resistance state, and the formation and destruction of the conductive channels modulated by oxygen vacancies have been suggested to be responsible for the nonvolatile resistive switching behaviors of the Au/α-Fe₂O₃/FTO memristors. Our results show the potential of the Au/α-Fe₂O₃/FTO memristors in nonvolatile memory applications.