Nath Shimul Kanti, Nandi Sanjoy Kumar, Ratcliff Thomas, Elliman Robert Glen
Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, Australian Capital Territory 2601, Australia.
ACS Appl Mater Interfaces. 2021 Jan 20;13(2):2845-2852. doi: 10.1021/acsami.0c19544. Epub 2021 Jan 6.
Two terminal metal-oxide-metal devices based on niobium oxide thin films exhibit a wide range of non-linear electrical characteristics that have applications in hardware-based neuromorphic computing. In this study, we compare the threshold-switching and current-controlled negative differential resistance (NDR) characteristics of cross-point devices fabricated from undoped NbO and Ti-doped NbO and show that doping offers an effective means of engineering the device response for particular applications. In particular, doping is shown to improve the device reliability and to provide a means of tuning the threshold and hold voltages, the hysteresis window, and the magnitude of the negative differential resistance. Based on temperature-dependent current-voltage characteristics and lumped-element modelling, these effects are attributed to doping-induced reductions in the device resistance and its rate of change with temperature (i.e., the effective thermal activation energy for conduction). Significantly, these studies also show that a critical activation energy is required for devices to exhibit NDR, with doping providing an effective means of engineering the current-voltage characteristics. These results afford an improved understanding of the physical mechanisms responsible for threshold switching and provide new insights for designing devices for specific applications.
基于氧化铌薄膜的双端金属-氧化物-金属器件展现出广泛的非线性电学特性，这些特性在基于硬件的神经形态计算中具有应用价值。在本研究中，我们比较了由未掺杂的NbO和Ti掺杂的NbO制成的交叉点器件的阈值开关和电流控制负微分电阻（NDR）特性，并表明掺杂为针对特定应用设计器件响应提供了一种有效手段。特别是，掺杂被证明可以提高器件可靠性，并提供一种调节阈值电压和保持电压、滞后窗口以及负微分电阻大小的方法。基于温度依赖的电流-电压特性和集总元件建模，这些效应归因于掺杂导致的器件电阻及其随温度变化率的降低（即传导的有效热激活能）。值得注意的是，这些研究还表明，器件要表现出NDR需要一个临界激活能，而掺杂为设计电流-电压特性提供了一种有效手段。这些结果有助于更好地理解负责阈值开关的物理机制，并为设计特定应用的器件提供新的见解。
