Solution-Processed ZnO/V2O5Heterojunction Thin Films for UV Photodetectors

Abstract

This study delineates the fabrication and evaluation of a high-performing ultraviolet (UV) photodetector (PD) consisting of a ZnO/V<inf>2</inf>O<inf>5</inf>nanoparticle (NP) bilayer thin film deposited on a Si/SiO<inf>2</inf>substrate through spin coating. Various analytical techniques, such as X-ray diffraction, Raman spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy, have been employed to investigate the structural features and surface morphology of the as-prepared samples. The V<inf>2</inf>O<inf>5</inf>NPs were prepared through a facile one-pot solvothermal process, while ZnO NPs were obtained through a rapid sol–gel method. V<inf>2</inf>O<inf>5</inf>NPs demonstrate extended absorption with significant absorption in the range of 240–450 nm and exhibit a relatively smaller band gap. The optoelectronic features of as-deposited thin films have primarily been studied through I–V characteristics under dark and UV light conditions with the same external bias of 2 V, and the photocurrent has been found to be 9.13 × 10–5A/cm2, which is ∼2.77 × 103times higher than the dark current. The obtained photocurrent-to-dark current ratio for the ZnO/V<inf>2</inf>O<inf>5</inf>device is nearly ∼1.37 × 102times higher than that of the ZnO-only device. Moreover, this bilayer UV PD exhibits a detectivity (D) of ∼3.1 × 1012Jones, a spectral responsivity (R) of ∼4 A/W, and an external quantum efficiency (EQE) of ∼16% under an external potential of 10 V. Furthermore, the findings are analyzed, and an explanation of the detailed photodetection mechanism is outlined in this paper. © 2025 American Chemical Society