Łapińska Anna, Kuźniewicz Michał, Gertych Arkadiusz P, Czerniak-Łosiewicz Karolina, Żerańska-Chudek Klaudia, Wróblewska Anna, Świniarski Michał, Dużyńska Anna, Judek Jarosław, Zdrojek Mariusz
Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland.
Materials (Basel). 2020 Nov 24;13(23):5315. doi: 10.3390/ma13235315.
We report a surfactant-free exfoliation method of WS flakes combined with a vacuum filtration method to fabricate thin (<50 nm) WS films, that can be transferred on any arbitrary substrate. Films are composed of thin (<4 nm) single flakes, forming a large size uniform film, verified by AFM and SEM. Using statistical phonons investigation, we demonstrate structural quality and uniformity of the film sample and we provide first-order temperature coefficient χ, which shows linear dependence over 300-450 K temperature range. Electrical measurements show film sheet resistance R = 48 MΩ/Υ and also reveal two energy band gaps related to the intrinsic architecture of the thin film. Finally, we show that optical transmission/absorption is rich above the bandgap exhibiting several excitonic resonances, and nearly feature-less below the bandgap.
我们报道了一种结合真空过滤法的无表面活性剂剥离WS薄片的方法，用于制备可转移到任意衬底上的薄（<50 nm）WS薄膜。薄膜由薄（<4 nm）的单个薄片组成，形成大尺寸均匀薄膜，这通过原子力显微镜（AFM）和扫描电子显微镜（SEM）得到验证。通过统计声子研究，我们证明了薄膜样品的结构质量和均匀性，并提供了一阶温度系数χ，其在300 - 450 K温度范围内呈线性依赖关系。电学测量表明薄膜的薄层电阻R = 48 MΩ/□，还揭示了与薄膜固有结构相关的两个能带隙。最后，我们表明，在带隙以上光传输/吸收丰富，表现出多个激子共振，而在带隙以下几乎没有特征。
