【Device Papers】Defect engineering of vertically aligned WO₃/β-Ga₂O₃ Heterostructure nanowires for improved UV Photodetection

      Researchers from National Institute of Technology Nagaland have published a dissertation titled " Defect engineering of vertically aligned WO₃/β-Ga₂O₃ Heterostructure nanowires for improved UV Photodetection " in Materials Science and Engineering: B.

Abstract

      Vertically aligned WO₃/β-Ga₂O₃ heterostructure (HS) nanowire (NW) arrays were deposited utilising a GLAD system RF magnetron sputtering system on a p-type Si substrate. The NWs were subsequently annealed in air at different temperatures ranging from 300 °C to 700 °C. The notable enhancement in the crystallinity and surface morphology of the synthesized vertical WO₃/β-Ga₂O₃ axial HS NWs was clearly observed in the samples with annealing. In the proposed WO₃/β-Ga₂O₃ HS, β-Ga₂O₃ serves as an electron transport/window layer under UV-A illumination. Moreover, the favourable band alignment at the WO₃/β-Ga₂O₃ interface promotes carrier collection at the top electrode while limiting hole transport, thereby improving photodetection. An overall red shift in the optical bandgap was observed with the rise in annealing temperature. The defect levels diminished at the annealed temperature of 600 °C, as indicated by the photoluminescence (PL) analysis, XRD and absorption data. The device fabricated with 600 °C sample also demonstrated superior UV photodetection at 400 nm, achieving a photo-to-dark current ratio (PDCR) of 0.99×10⁴, a large responsivity of 78.58 AW^-1，and rise/fall times of 0.27 s/9 ms. These results reveal that by controlled air annealing, the structural and interfacial properties of WO₃/β-Ga₂O₃ axial NWs can be modified to achieve superior UV- A photodetection characteristics.

DOI:

https://doi.org/10.1016/j.mseb.2026.119865