Preparation of WS2 films with (002) plane preferred orientation and its formation mechanism

Abstract

Materials with oriented structures exhibit excellent mechanical, electrical, and tribological properties. In this study, WS2 films with a preferred orientation along the (002) plane were prepared using shear flow technology, and the influence of polyvinyl alcohol (PVA) concentration and wedge angle on the oriented structure of the WS2 films was systematically studied. The results indicated that the diffraction peak intensity ratio of the (002) and (103) planes of the WS2 films (I(002)/I(103)), increased from 46.68 to 116.11 when the PVA concentration increased from 5 to 25 g/L. When the wedge angle increased from 5° to 40°, I(002)/I(103) showed a similar trend, increasing from 80.99 to 347.22. Thus, the higher I(002)/I(103) value confirmed a preferred (002) plane orientation of WS2 in the films, indicating that an increase in PVA concentration and wedge angle significantly enhanced the shear stress of the slurry. Under shear stress, the WS2 particles had a tendency to orient along the shear stress direction, forming a preferred (002) plane-oriented structure. Therefore, this research may provide theoretical and technical support for preparing preferred orientation 2D materials.