Synthesis and characterization of tungsten disulfide thin films by spray pyrolysis technique for n-WS2/p-Si junction diode application.

Tungsten disulfide (WS₂) thin films were deposited on the glass substrate by varying its temperature from 350 to 500 °C using jet nebulizer spray pyrolysis (JNSP) technique. The WS₂ thin films were characterized through various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX), UV-Visible spectroscopy (UV), photoluminescence (PL), Hall measurements and current-voltage (I-V) characteristics. XRD pattern revealed that the prepared WS₂ films are polycrystalline in nature with rhombohedral and hexagonal crystal structures. The average crystallite size of WS₂ thin films changed from 52.23 to 47.40 nm. SEM images showed the uniform grain size, which is agglomerated at the higher substrate temperature. The presence of elements like W and S was confirmed through EDX spectrum. From UV analysis, the minimum optical band gap and maximum absorption was obtained for the film deposited at 450 °C. The WS₂ thin films exhibited an n-type semiconductor nature with the carrier concentration of 10¹⁴ cm⁻³, which was demonstrated through hall measurements. Also, the electrical resistivity of the WS₂ films varied from 3.26 × 10⁵ to 1.59 × 10⁷ Ω cm. The p-Si/n-WS₂ junction diode was fabricated with various substrate temperature of (350-500 °C). Junction diode parameters like ideality factor (n), barrier height (ϕ_B) and reverse saturation current (I_o) values were calculated and interpreted based on the thermionic emission theory model. [ABSTRACT FROM AUTHOR]