The Discovery of a High-Mobility Two-Dimensional Bismuth Oxyselenide Semiconductor and Its Application in Nonvolatile Neuromorphic Devices
Yuyu He, Qi Xu, Xinyue Dong, Junhao Liu, Li Li, Bing Wang, Jiabiao Chen, Lei Zhang, Zhansheng Gao, Wei Ai, Zhaochao Liu, Zhengyang Zhou, Weigao Xu, Huixia Fu, Feng Luo, Jinxiong Wu
Abstract
The development of two-dimensional (2D) electronics is always accompanied by the discovery of 2D semiconductors with high mobility and specific crystal structures, which may bring revolutionary breakthrough on proof-of-concept devices and physics. Here, Bi 3 O 2.5 Se 2, a 2D bismuth oxyselenide semiconductor with non-neutral layered crystal structure is discovered. Ultrathin Bi 3 O 2.5 Se 2 films are readily synthesized by chemical vapor deposition, displaying tunable band gaps and high room-temperature field-effect mobility of >220 cm 2 V –1 s –1 . Moreover, the as-synthesized Bi 3 O 2.5 Se 2 nanoplates were fabricated into top-gated transistors with a simple device configuration, whose carrier density can be reversibly regulated in the range of 10 14 cm –2 just by a facile method of electrostatic doping at room temperature. These features enable it to be functionalized into nonvolatile synaptic transistors with ultralow operating energy consumption (∼0.5 fJ), high repeatability, low operating voltage (0.1 V), and long retention time. Our work extends the family of bismuth oxyselenide 2D semicondutors.