Optical and electrical characterization of WS 2 multilayer on flexible PET substrate

WS 2 is two-dimensional layered material which the electronic band gap is dependent on the number of layers. From application point of view, the WS 2 few layers are good candidate for nano scale flexible electronics . In this study, the WS 2 number of layers is modified using liquid phase exfoliation method. The blue shift of WS 2 supernatant absorption peaks suggested the change of layer thickness compare to the non-exfoliated one. This supernatant is further deposited on Polyethylene terephthalate (PET) to create a flexible multilayer WS 2 thin films. The morphology and the content of the thin film are confirmed by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), respectively. The Raman and photoluminescence spectroscopy show typical characteristics of WS 2 multilayers which are dominated by W-S vibrations, exciton contributions, as well as the local defect and strain effects. Furthermore, the electrical characterization reveals the robustness of the WS 2 electronic properties again the mechanical stretching. This study highlights the abundant optical and electrical characterization of WS 2 multilayer which are applicable for flexible electronic devices.