铁酸铋薄膜在小于矫顽电压下的阻变机制

为了研究利用脉冲激光沉积法制备于SrTiO_3衬底上的Au/BiFeO_3/SrRuO_3结构的阻变效应,实验通过测量样品的I-V特性曲线来表征样品的阻态变化.由于BiFeO_3与Au、SrRuO_3功函数的不同在Au/BiFeO_3、BiFeO_3/SrRuO_3两个接触界面形成稳定的肖特基接触,通过改变外部电压控制陷阱能级填充的程度可以改变肖特基势垒高度,从而在施加电压小于矫顽电压时可以形成稳定的高低阻变化,表现出最大可达103高低阻电流比的I-V特性曲线.对I-V特性曲线进行不同导电机制的拟合表明:小于矫顽电压下空间电荷限制电流起到了主导作用,陷阱的填充与脱陷是主要的阻变机制.

Resistive Switching Effect of BiFeO3 Thin Film Under the Voltage Below the Coercive Voltage

To study the resistive effect of the Au/BiFeO3/SrRuO3 fabricated by the pulsed laser deposition on the SrTiO3 substrate, the resistive effect was characterized by the Ⅰ-Ⅴ curves. Due to the different work function between BiFeO3 and Au, BiFeO3 and SrRuO3 , the stable Shottky contact was formed between the contact surface of Au/BiFeO3 and BiFeO3/SrRuO3 . The Shottky barrier height was changed by application of external voltage to control the filling status of trap levels. Results show that from the Ⅰ-Ⅴ curve the film displays the resistive switching behavior under the voltage below the coercive voltage, with the resistance ratio as large as three orders. Through the fitting of Ⅰ-Ⅴ curves by different conduction mechanisms, it is confirmed that the conduction of the film is dominated by the space charge limited current ( SCLC) . The trapping effect was proposed as the resistive switching mechanism for the BiFeO3 thin film below the coercive voltage.