Welcome to The Thin Film Team

The development of efficient and cost-effective semiconductor thin film materials to replace precious metals for the application of photocatalysis is of intense research focus. Transition metal dichalcogenides are becoming an increasingly attractive candidate due to their tunable optical and electrical properties. However, conventional thin film fabrication methods can be quite costly and cumbersome. Herein we developed a highly accessible and facile solution-based method for developing device quality molybdenum disulfide (MoS2) and tungsten disulfide (WS2) semiconductor thin films using molecular precursors through a spin-coating technique. In addition, we fabricated templates of close-packed hexagonal polystyrene microspheres (500 nm) to create inverse opal structured MoS2 and WS2 semiconductors. Structural, optical, and electrical properties of the thin films were characterized by powder X-ray diffraction (PXRD), UV-Vis spectroscopy, and four-point probe, respectively. PXRD shows a clear transition from amorphous to crystalline structure between annealing temperatures of 300-500 °C. The MoS2 and WS2 thin films exhibited bandgaps of 1.55 ± 0.06 eV and 1.80 ± 0.10 eV, respectively, which are suitable for photocatalysis. Four-point probe measurements exhibited that as the annealing temperature increases, the resistance also increases. We also investigated the electrical and optical properties of Co and Ni-doped MoS2 semiconductors. Doping lowered the bandgaps slightly, and Ni-doped MoS2 films showed a decrease in resistance; however, Co-doped films had a slightly higher resistance compared to undoped MoS2 films. Preliminary cyclic voltammetry measurements show promise for hydrogen evolution. These protocols provide viable routes for producing thin films and nanoporous templates without requiring expensive equipment and extreme conditions.