Nanoscale|一种具有铁电性的二维SnSe薄膜及其生物现实突触的应用 ...

文章链接：https://doi.org/10.1039/D0NR03724A

Au/SnSe/NSTO人工神经元

摘要

迎合人工智能发展的大趋势，模拟人类的学习和思维行为已成为研究热点。二阶记忆电阻器更类似于生物突触，是目前最有希望用于神经形态/类脑计算的设备。然而，基于二维(2D)材料的二阶记忆电阻器鲜有报道，其内在的仿生物理还有待探索。利用脉冲激光沉积技术制备了一种基于二维SnSe薄膜的二阶记忆电阻。Au/SnSe/NSTO结构电导的可连续调节是通过逐渐改变铁电SnSe层的极化来实现的。实验结果表明，利用该双端器件可以模拟生物突触功能，包括脉冲时间依赖可塑性、短期可塑性和长期可塑性。此外，脉冲持续时间为纳秒的刺激脉冲被应用到该设备上，以模拟人类大脑中的快速学习和长期记忆。在SnSe/NSTO界面上，耗尽层宽度的调制主要影响了薄膜的记忆行为，而铁电极化的反转也影响了薄膜的势垒高度。该器件能耗低至66fJ，有望应用于小型化、高密度、低功耗的神经形态计算。

Catering to the general trend of artificial intelligence development, simulating humans’ learning and thinking behavior has become the research focus. Second-order memristors, which are more analogous to biological synapses, are the most promising devices currently used in neuromorphic/brain-like computing. However, few second-order memristors based on two-dimensional (2D) materials have been reported, and the inherent bionic physics needs to be explored. In this work, a second-order memristor based on 2D SnSe films was fabricated by the pulsed laser deposition technique. The continuously adjustable conductance of Au/SnSe/NSTO structures was achieved by gradually switching the polarization of a ferroelectric SnSe layer. The experimental results show that the bio-synaptic functions, including spike timing-dependent plasticity, short-term plasticity and long-term plasticity, can be simulated using this two-terminal devices. Moreover, stimulus pulses with nanosecond pulse duration were applied to the device to emulate rapid learning and long-term memory in the human brain. The observed memristive behavior is mainly attributed to the modulation of the width of the depletion layer and barrier height is affected, at the SnSe/NSTO interface, by the reversal of ferroelectric polarization of SnSe materials. The device energy consumption is as low as 66 fJ, being expected to be applied to miniaturized, high-density, low-power neuromorphic computing