Floating-gate photosensitive synaptic transistors with tunable functions for neuromorphic computing  

用于神经形态计算的具有可调功能的浮栅光敏突触晶体管

作　　者：Lingkai Li Xiao-Lin Wang Junxiang Pei Wen-Jun Liu Xiaohan Wu David Wei Zhang Shi-Jin Ding 李凌凯;王晓琳;裴俊翔;刘文军;吴小晗;张卫;丁士进(State Key Laboratory of ASIC and System,School of Microelectronics,Fudan University,Shanghai 200433,China)

机构地区：[1]State Key Laboratory of ASIC and System,School of Microelectronics,Fudan University,Shanghai 200433,China

出　　处：《Science China Materials》2021年第5期1219-1229,共11页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China (61874029)。

摘　　要：Synaptic devices that merge memory and processing functions into one unit have broad application potentials in neuromorphic computing, soft robots, and humanmachine interfaces. However, most previously reported synaptic devices exhibit fixed performance once been fabricated,which limits their application in diverse scenarios. Here, we report floating-gate photosensitive synaptic transistors with charge-trapping perovskite quantum dots(PQDs) and atomic layer deposited(ALD) Al_(2)O_(3) tunneling layers, which exhibit typical synaptic behaviors including excitatory postsynaptic current(EPSC), pair-pulse facilitation and dynamic filtering characteristics under both electrical or optical signal stimulation. Further, the combination of the high-quality Al2O3 tuning layer and highly photosensitive PQDs charge-trapping layer provides the devices with extensively tunable synaptic performance under optical and electrical co-modulation. Applying light during electrical modulation can significantly improve both the synaptic weight changes and the nonlinearity of weight updates, while the memory effect under light modulation can be obviously adjusted by the gate voltage.The pattern learning and forgetting processes for "0" and "1"with different synaptic weights and memory times are further demonstrated in the device array. Overall, this work provides synaptic devices with tunable functions for building complex and robust artificial neural networks.将记忆和处理功能整合为一个单元的突触器件在神经形态计算、软机器人和人机交互等方面具有广泛的应用潜力.然而,先前报道的大多数突触器件一旦制造出来就表现出固定的性能,这限制了它们在不同场景中的应用.在这里,我们报道了一种以钙钛矿量子点为电荷俘获层、以原子层沉积的Al_(2)O_(3)为隧穿层的浮栅光敏突触晶体管.在电或者光信号的刺激下,该器件都能展示出典型的突触行为,包括兴奋性突触后电流、双脉冲异化和动态滤波特性.进一步地,器件中高质量Al_(2)O_(3)隧穿层和高光敏的钙钛矿量子点电荷俘获层使得其突触可塑性可以在光和电信号的共同调制下实现大范围的调节.在电调制过程中施加光信号可以显著改善突触权重的变化和权值更新的非线性,而光调制下的记忆效应可以明显地受到栅极电压的调节.该器件的阵列进一步展示了对图案"0"和"1"的不同突触权重或记忆时间的学习和遗忘过程.综上,这项工作为构建复杂而稳固的人工神经网络提供了具有可调功能的突触器件.

关 键 词：synaptic device floating-gate transistor perovskite quantum dot tunable synaptic function optical and electrical comodulation 

分 类 号：TN32[电子电信—物理电子学]