Nanostructured metal sulphides are gaining attention as potential materials for resistive chemical sensors due to their high electrical conductivity and chemical stability compared to metal oxides. Among these, tungsten disulfide (WS₂), a transition metal dichalcogenide (TMD), stands out because of its distinctive electrical, optical, and mechanical properties. In this study, WS₂ thin films were synthesized on glass substrates using the spray pyrolysis technique. Structural and electrical characterizations revealed a highly porous, granular morphology with nanoparticle agglomerations, as observed through FESEM. XRD analysis confirmed a well-crystallized hexagonal WS₂ phase with an average crystallite size of 35.81 nm. The films exhibited a resistivity of 9.26 × 10⁶ Ω cm and a negative temperature coefficient of resistance (-0.00097/°C), indicating semiconducting behaviour. Gas sensing tests showed exceptional NO₂ sensitivity (94.25%) and selectivity at 60°C, with rapid response (11 s) and recovery (57 s) times, confirming WS₂’s potential for efficient low-temperature gas sensing applications.
Yewale et al. (Thu,) studied this question.