Kim Jihoon, Choi Sungwook, Lee Seul-Lee, Kim Do Kyung, Kim Min Seok, Kim Bong-Jun, Lee Yong Wook
School of Electrical Engineering, Pukyong National University, 45 Yongso-ro, Nam-gu, Busan 48513, Korea.
Interdisciplinary Program of Biomedical Mechanical & Electrical Engineering, Pukyong National University, 45 Yongso-ro, Nam-gu, Busan 48513, Korea.
J Nanosci Nanotechnol. 2021 Mar 1;21(3):1862-1868. doi: 10.1166/jnn.2021.18905.
In this study, we implemented reversible current switching (RCS) of 100 mA in a two-terminal device based on a vanadium dioxide (VO₂) thin film, which could be controlled by far-infrared (FIR) laser pulses. The VO₂ thin films used for fabrication of two-terminal devices were grown on sapphire (Al₂O₃) substrates using a pulsed laser deposition method. An optimal deposition condition was determined by analyzing the resistance-temperature curves of deposited VO₂ thin films and the current-voltage characteristics of two-terminal devices based on these films, which were suggested in our previous works. The film surface of the VO₂-based device was directly irradiated using focused CO₂ laser pulses, and the insulator-metal transition or metal-insulator transition of the VO₂ thin film could be triggered depending on laser irradiation. Consequently, RCS of up to 100 mA could be accomplished. This on-state current is close to the upper limit of the current flowing through our VO₂ device. The switching contrast, defined as the ratio between on-state and off-state currents, was evaluated and found to be ˜11,962. The average rising and falling times of the switched current were found to be ˜29.2 and ˜71.7 ms, respectively. In comparison with our previous work, the improved heat dissipation structure and the high-quality thin film could maintain the switching contrast at a similar level, although the on-state current was increased by about two times.
在本研究中，我们在基于二氧化钒（VO₂）薄膜的两终端器件中实现了100 mA的可逆电流切换（RCS），该切换可由远红外（FIR）激光脉冲控制。用于制造两终端器件的VO₂薄膜采用脉冲激光沉积法生长在蓝宝石（Al₂O₃）衬底上。通过分析沉积的VO₂薄膜的电阻 - 温度曲线以及基于这些薄膜的两终端器件的电流 - 电压特性来确定最佳沉积条件，这些内容在我们之前的工作中已有提及。使用聚焦的CO₂激光脉冲直接照射基于VO₂的器件的薄膜表面，根据激光照射情况可以触发VO₂薄膜的绝缘体 - 金属转变或金属 - 绝缘体转变。因此，可以实现高达100 mA的RCS。该导通状态电流接近流过我们的VO₂器件的电流上限。评估了定义为导通状态电流与截止状态电流之比的开关对比度，发现约为11,962。开关电流的平均上升和下降时间分别约为29.2 ms和71.7 ms。与我们之前的工作相比，尽管导通状态电流增加了约两倍，但改进的散热结构和高质量薄膜能够将开关对比度维持在相似水平。
