Influence of oxygen partial pressure on the performance of MoO3-based ultraviolet photodetectors

To save our motherland from the harmful ultraviolet (UV) ray, the essentiality of UV photodetectors is increasing gradually. Herein, the MoO3-x thin films are deposited onto the SiO2/Si substrates through a sputtering technique by varying the oxygen partial pressure (pO2) at a substrate temperature of 200°C to examine the UV photodetector performance. It is observed that the thickness of the thin film is decreased with an increase in the pO2 due to the less ejection of atoms from the oxidized target surface. Structural study confirms the improved crystalline nature of the thin film deposited at 5.0% of pO2 and results in better electrical properties. The photodetector performance under UV illumination is studied as a function of pO2. The linear behavior of the current-voltage (I-V) characteristics attests to the ohmic contact nature between the photoactive layer (MoO3-x) and the metal (Ag) electrode interface. The fabricated photodetector test-device achieves a high photocurrent of 11.22 µA, a fast response time of 100 ms, and a superior responsivity of 1.537 A/W even at a lower optical power density of 0.0292 mW/cm2. Finally, these enhanced figures of merit of the MoO3-based photodetector could show a significant path toward the development of fast UV photodetector and optoelectronic devices.