Effect of nanosecond and femtosecond pulse laser on the formation of WS2 nanostructures and field emission characteristics

Abstract

The pulse laser ablation is a simple and direct method used for the generation of nanostructures in liquid environment. In this paper, formation of tungsten sulfide [Formula: see text] nanostructures has been carried out using nanosecond (ns) and femtosecond (fs) laser ablation with ablation time 120 min. In addition, the field emission studies were performed of the prepared sample. The characterization techniques such as the transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-visible spectroscopy have been used to confirm the surface morphology as well as structural details. It is observed that the laser pulse regime plays a vital role on the size reduction of [Formula: see text] nanostructure. The X-ray spectra reveal the formation of [Formula: see text] nanoparticles for ns laser ablation, while [Formula: see text] nanosheets for fs laser ablation. The TEM images indicate that the transformation of [Formula: see text] microsheet into nanosheet of the size about 15–200 nm for the sample treated with ns laser and fs laser ablation. Also, the results clearly shows the improvement in the field emission characteristics for laser ablated [Formula: see text] nanosheets. The enhanced field emission characteristics is attributed to the formation and separation of few layer [Formula: see text] nanosheets. The [Formula: see text] nanostructures may have great potential for the applications in optoelectronic devices.