Simulation and deposition of Tungsten oxide (WO3) films using DC sputtering towards UV photodetector for high responsivity

Tungsten trioxide (WO₃) detects UV radiation with great sensitivity while disregarding visible light, and it also has excellent electron mobility, allowing for efficient charge transport and fast response times. This work aims to develop a highly sensitive UV photodetector using WO₃ material by optimizing the deposition parameter partial oxygen pressure (PaO₂) and annealing the samples at various temperatures to determine the best PaO₂ and annealing temperature that results in an improvement in the UV photodetector's sensitivity. The material WO₃ was coated on glass substrates using DC magnetron sputtering while altering the PaO₂ as 6 × 10⁻² Pa, 4 × 10⁻² -2 Pa, and 2 × 10⁻² Pa, and then each as-deposited sample from varied PaO₂ was annealed at temperatures ranging from 100°C to 400°C. When the sample's responses were compared, it was observed that the sample deposited at PaO₂ 2 × 10⁻² Pa and annealed at 400 °C exhibited good photodetection capabilities, as evidenced by several characterization techniques such as SEM, XRD, and IV characterization. The work was subsequently carried out by evaluating the sample deposited at PaO₂ 2 × 10⁻² Pa and annealed at 700 °C, which produced a good result for UV photodetection with the device's responsivity of 1e+4 A/W.