Optimization of Tungsten Trioxide (Wo3) Thin Films Using RF Sputtering Towards UV Photo Detector Application

A significant concern arises over the possible adverse effects of ultraviolet (UV) radiation, particularly the UVA spectrum ($320-400 \mathrm{~nm}$), on human skin and the human body. The primary objective of this study is to design and fabricate a UV photodetector utilizing Tungsten Trioxide WO3, a photoactive material that has favorable characteristics for detecting the UVA spectrum as it demonstrates a bandgap within the range of 2.7 to 2.8 electron volts (eV), allowing the detection of wavelengths approximately spanning from 300 to 395 nanometers (nm). Material was deposited on a glass substrate using an RF sputtering system at a partial pressure of $4 \mathrm{e}-2$ Pascal. The resulting sample was subsequently subjected to investigation at different temperatures, ranging from Room temperature to $200^{\circ} \mathrm{C}$, through the process of annealing. Additionally, the provided sample underwent characterization to verify the efficacy of the created device in detecting the UVA spectrum. Material characterization was performed using a Scanning Electron Microscope (SEM) and X-ray diffraction (XRD). The efficacy of UV light detection is contingent upon the responsiveness of the instrument. On the application of a voltage across the device in the range of -3 V to 3 V and UV light of 395 nm wavelength it is observed that the sample deposited at a partial pressure of $4 \mathrm{e}-2$ pascal and annealed at $200^{\circ} \mathrm{C}$ provided a higher responsivity of $3.99 \mathrm{E}-07 \mathrm{~A} / \mathrm{W}$ in comparison to other annealed samples.