The photodetector characteristics of the molybdenum oxide-based heterostructure fabricated at varying oxygen and argon gas flow rates via the reactive DC magnetron sputtering

This study investigates the structure and photodetector properties of MoO_3-x/p-Si heterojunction grown by reactive DC magnetron sputtering in varying O₂/Ar gas flow rates. The X-ray diffraction study revealed the presence of α-MoO₃ and sub-oxide phases Mo₅O₁₄ with the predominance of α-MoO₃ observed in all thin films. It was observed that the prepared samples showed high transmittance values of about 80%. The FESEM images showed that the prepared samples have flake-like structures. An increase in oxygen content resulted in a compact/dense morphology and a noticeable decrease in the size of the grains. The best performance of the photodiodes is achieved by the sample (O₂/Ar = 3/12), which has better crystal quality and a low dark saturated current density (0.06 μA/cm²) compared to others. This sample shows the greatest photoresponse ratio (I_Light/I_Dark) of 569 and 812 when exposed to UV and IR light. The MoO₃/p-Si heterojunction device demonstrates rapid switching properties, with fast rise and decay times in the 7–32 ms range.