Wang He, Huang Chung-Che, Polcar Tomas
National Centre for Advanced Tribology, Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, UK.
Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, UK.
Sci Rep. 2019 Aug 29;9(1):12570. doi: 10.1038/s41598-019-49107-y.
Triboelectric properties of chemical vapor deposited WS nanoflakes have been characterized in nano-range by atomic force microscopy (AFM) and Kelvin force microscopy (KFM). The triboelectric process is dependent on the thickness of WS nanoflakes, and it is sensitive to the adsorbates like water molecules, as well as transferred Pt from the tip on the sample. The density of tribo-charge can be modified by applying various biases to the conductive Pt-coated tip during the frictional process. Tunneling of the tribo-charge into the gap between WS and the underlying substrate results in a long lifetime, which is about 100 times longer than conventional triboelectric charges. Moreover, we observe a positive correlation between the layer number and resistance to charge dissipation. Our finding can become the driving force for a new category of two-dimensional (2D) WS triboelectrically controllable nanodevices.
通过原子力显微镜（AFM）和开尔文力显微镜（KFM）在纳米尺度上对化学气相沉积的WS纳米薄片的摩擦电性能进行了表征。摩擦电过程取决于WS纳米薄片的厚度，并且对诸如水分子等吸附物以及从样品尖端转移的Pt敏感。在摩擦过程中，通过对导电的涂覆Pt的尖端施加各种偏压，可以改变摩擦电荷的密度。摩擦电荷隧穿到WS与下层衬底之间的间隙中会导致较长的寿命，这比传统的摩擦电荷长约100倍。此外，我们观察到层数与电荷耗散电阻之间存在正相关。我们的发现可以成为新型二维（2D）WS摩擦电可控纳米器件的驱动力。
