An Fe-doped ZnO/BiVO4 heterostructure-based large area, flexible, high-performance broadband photodetector with an ultrahigh quantum yield

Abstract

Pristine ZnO has been widely explored for its use in UV photodetectors; however, the utility of ZnO in broadband photodetectors is still a challenge as it absorbs in the UV region only with low quantum efficiency and responsivity that can be accredited to the high recombination rate of photo-generated charge carriers. To address this issue, we report an Fe-doped 2D ZnO thin film, obtained through band gap engineering, and a 1D electrospun mixed-inorganic monoclinic BiVO₄ nanofiber heterostructure on an ITO-coated PET substrate-based broadband photodetector (PD) with ultra-high responsivity and EQE values in comparison to PDs fabricated using expensive cleanroom techniques. BiVO₄ plays the dual role of absorbing photons in the visible and NIR regions and creating local electric fields at the interface of the Fe-doped ZnO (FZO)–BiVO₄ heterostructure, which helps in the separation of electron–hole pairs. The robustness of the flexible PD was further examined under the conditions of repeated bending cycles (up to 500), yielding a stable response. The responsivity values obtained for UV, visible and NIR irradiation are 7.35 A W⁻¹, 3.8 A W⁻¹ and 0.18 A W⁻¹ with very high EQE values of 2501.7%, 851.2% and 28.3%, respectively. The facile and cost-effective fabrication of the device with high performance provides a new approach for developing flexible electronics and high-performance optoelectronic devices.