Kim Hyung Jun, Park Daehoon, Yang Paul, Beom Keonwon, Kim Min Ju, Shin Chansun, Kang Chi Jung, Yoon Tae-Sik
Department of Materials Science and Engineering, Myongji University, Gyeonggi-do 17058, Republic of Korea.
Nanotechnology. 2018 Jun 29;29(26):265204. doi: 10.1088/1361-6528/aabcf6. Epub 2018 Apr 10.
A crossbar array of Pt/CeO/Pt memristors exhibited the synaptic characteristics such as analog, reversible, and strong resistance change with a ratio of ∼10, corresponding to wide dynamic range of synaptic weight modulation as potentiation and depression with respect to the voltage polarity. In addition, it presented timing-dependent responses such as paired-pulse facilitation and the short-term to long-term memory transition by increasing amplitude, width, and repetition number of voltage pulse and reducing the interval time between pulses. The memory loss with a time was fitted with a stretched exponential relaxation model, revealing the relation of memory stability with the input stimuli strength. The resistance change was further enhanced but its stability got worse as increasing measurement temperature, indicating that the resistance was changed as a result of voltage- and temperature-dependent electrical charging and discharging to alter the energy barrier for charge transport. These detailed synaptic characteristics demonstrated the potential of crossbar array of Pt/CeO/Pt memristors as artificial synapses in highly connected neuron-synapse network.
由铂/二氧化铈/铂忆阻器组成的交叉阵列展现出了突触特性，比如模拟、可逆以及具有约10倍的强电阻变化，这对应着突触权重调制的宽动态范围，即相对于电压极性的增强和抑制。此外，它还呈现出与时间相关的响应，比如双脉冲易化以及通过增加电压脉冲的幅度、宽度和重复次数并减小脉冲之间的间隔时间实现从短期记忆到长期记忆的转变。随时间的记忆损失符合拉伸指数弛豫模型，揭示了记忆稳定性与输入刺激强度之间的关系。随着测量温度升高，电阻变化进一步增强但其稳定性变差，这表明电阻变化是由于电压和温度依赖的充电和放电导致电荷传输的能垒改变所致。这些详细的突触特性证明了铂/二氧化铈/铂忆阻器交叉阵列在高度连接的神经元 - 突触网络中作为人工突触的潜力。
