Investigation of Yttrium (Y)-doped ZnO (Y:ZnO)–Ga2O3 core-shell nanowire/Si vertical heterojunctions for high-performance self-biased wideband photodetectors.

High interfacial area, less surface defects and wide light absorption capability of core-shell nanowire heterojunctions are broadly accepted as a potential candidate for self-biased, high-speed photodetectors. In the current study, Y:ZnO–Ga₂O₃ core-shell nanowires' heterojunctions are fabricated by employing sequential double-step chemical bath deposition (CBD) and radio -frequency (RF) sputtering techniques on Si substrate. The ultra-thin highly transparent Ga₂O₃ (~ 15 nm) layer reduces the surface states of Y:ZnO nanowires in a significant amount and such core-shell heterojunction deals with the development of low power white light-responsive detectors by combining Y:ZnO and Ga₂O₃. The crystallinity, structure, chemical states and light absorption properties of the Y:ZnO–Ga₂O₃ core-shell nanowires are analysed in detail by using XRD, FESEM, HRTEM, EDS, XPS and UV-Visible spectroscopy. The fabricated core-shell Y:ZnO–Ga₂O₃ nanowire/Si heterojunction exhibits p–n junction behaviour and it exhibits self-powered photoresponse under Xe lamp with AM 1.5 G (100 W/cm²) filter. A low dark current of ~ 1.74 × 10^{− 11} A, high photo-to-dark current ratio of 3.2 × 10⁴ and rapid response speed of < 1 s are achieved from such core-shell heterojunction device and relevant photo-carrier generation mechanism is considered from energy band diagram. Therefore, current study provides a technological route to fabricate the next-generation self-powered core-shell heterojunction devices for photo-sensing applications. [ABSTRACT FROM AUTHOR]