Self-Powered Photodetector Based on p(Cu₂O)–n(MoO₃) Junction Architecture: Analyzing the Influence of Depletion Region Width on the Photodetector Properties

In this study, the fabrication of the p – n junction photodetector (PD) based on p -type Cu 2 O and n -type MoO 3 semiconductor, which shows a broadband photoresponse (ultraviolet to near-infrared) at self-powered mode, is presented. The thin films are grown through the sputtering technique by varying the depletion region width (DRW) by 2 mm, 3.5 mm, and 5 mm, and the photodetector properties are studied. The fabricated device with a DRW of 3.5 mm, depending on the generation of a stronger electric field, with less recombination of the charge carriers at the depletion region, results in achieving higher photodetector properties. Consequently, the Ag/Cu 2 O:MoO 3 /Ag@DRW of the 3.5 mm device shows the highest photocurrent of 16.6 and 39.12 nA under the illumination of 550 and 1000 nm wavelengths. Furthermore, the photodetector properties of the device fabricated on the polyethylene terephthalate (PET) substrate are studied by applying a bias voltage. At 5 V bias voltage and under the illumination of UV light, the Ag/Cu 2 O:MoO 3 /Ag@DRW of a 3.5 mm device grown on the PET substrate shows the R λ of 11.4 μA/W and D * of 1.45 × 10 6 Jones. Finally, these superior figures of merit of the fabricated device signify the development of the self-powered photodetector with broadband photodetection.