Guo Junmeng, Wen Rongmei, Zhai Junyi, Wang Zhong Lin
CAS Center for Excellence in Nanoscience, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China; School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
CAS Center for Excellence in Nanoscience, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China; School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing 100049, China; Center on Nanoenergy Research, School of Physical Science and Technology, Guangxi University, Nanning 530004, China.
Sci Bull (Beijing). 2019 Jan 30;64(2):128-135. doi: 10.1016/j.scib.2018.12.009. Epub 2018 Dec 7.
NO sensors with ultrahigh sensitivity are demanded for future electronic sensing systems. However, traditional sensors are considerably limited by the relative low sensitivity, high cost and complicated process. Here, we report a simply and reliable flexible NO sensor based on single-layer MoS. The flexible sensor exhibits high sensitivity to NO gas due to ultra-large specific surface area and the nature of two-dimensional (2D) semiconductor. When the NO is 400 ppb (parts per billion), compared with the dark and strain-free conditions, the sensitivity of the single-layer sensor is enhanced to 671% with a 625 nm red light-emitting diode (LED) illumination of 4 mW/cm power under 0.67% tensile strain. More important, the response time is dramatically reduced to ∼16 s and it only needs ∼65 s to complete 90% recovery. A theoretical model is proposed to discuss the microscopic mechanisms. We find that the remarkable sensing characteristics are the result of coupling among piezoelectricity, photoelectricity and adsorption-desorption induced charges transfer in the single-layer MoS Schottky junction based device. Our work opens up the way to further enhancements in the sensitivity of gas sensor based on single-layer MoS by introducing photogating and piezo-phototronic effects in mesoscopic systems.
未来的电子传感系统并不需要超高灵敏度的传感器。然而，传统传感器受到相对较低的灵敏度、高成本和复杂工艺的极大限制。在此，我们报道了一种基于单层MoS的简单且可靠的柔性NO传感器。由于具有超大的比表面积和二维（2D）半导体的特性，该柔性传感器对NO气体表现出高灵敏度。当NO浓度为400 ppb（十亿分之一）时，在0.67%的拉伸应变下，与黑暗且无应变的条件相比，单层传感器在4 mW/cm功率的625 nm红色发光二极管（LED）光照下，灵敏度提高到671%。更重要的是，响应时间大幅缩短至约16 s，仅需约65 s即可完成90%的恢复。我们提出了一个理论模型来讨论微观机制。我们发现，显著的传感特性是基于单层MoS肖特基结器件中压电、光电和吸附 - 解吸诱导电荷转移之间耦合的结果。我们的工作通过在介观系统中引入光门控和压光电效应，为进一步提高基于单层MoS的气体传感器的灵敏度开辟了道路。
