Reactive sputtering growth of Co3O4 thin films for all metal oxide device: a semitransparent and self-powered ultraviolet photodetector

All-oxide photodetectors-based on Co3O4 thin films are optimized and fabricated using large area reactive sputtering method. In particular, optical measurements of Co3O4 thin films show the presence of dual band gaps (Eg1 ~1.5 eV and Eg2 ~2 eV) and an average transmittance of 70% over the broad spectral range (300 − 1300 nm) is useful to realize the semitransparent all metal oxide photoelectric device. A Co3O4-based semitransparent, high-performing, self-biased, ultraviolet-operated photodetector with Co3O4/ZnO/ITO architecture presented. Addition to this, Co3O4 device over-coated by MoO3 as hole transporter shows advantage of selective contact, resulting three times improvement in the photoresponse with fast UV detection (33 ms). This study will pave the way to design cost-effective, semitransparent, and efficient cobalt oxide-based photodetectors as well as photovoltaics.