Ternary ZnO : CeO2/NiO heterostructure as a high-performance platform for ultraviolet photodetection.

Abstract

A ZnO : CeO₂/NiO ternary heterostructure with promising UV detection characteristics is introduced for the first time and was fabricated by a two-step process involving a hydrothermal method and spin-coating method. The XRD, SEM and EDX mapping results are in full agreement with the formation of a highly crystalline, phase-pure and homogeneously distributed ternary composite with a porous nanoflake morphology, which offers a high surface area for effective photon absorption and charge-carrier transport. The fabricated device demonstrates excellent optoelectronic properties under 5 V bias, with a high responsivity of about 165 mA W^-1, a specific detectivity of 4.8 × 10⁹ Jones and an external quantum efficiency (EQE) of 60% at 340 nm, which are much higher than those of pristine ZnO and binary ZnO : CeO₂. In addition, it is found that the photodetector has a high dynamic response speed (0.16 s for the response time and 0.25 s for the recovery time) and excellent operational stability and reproducibility for repeated switching cycles. The synergistic effect of CeO₂ and p-type NiO enhances photodetection performance. CeO₂ introduces intermediate energy states and helps control oxygen-vacancy-related defects, while NiO promotes efficient electron-hole separation and suppresses charge-carrier recombination. This also shows that the ZnO : CeO₂/NiO ternary heterostructure is a very attractive material for high-performance, environmentally friendly, energy-autonomous UV photodetectors for future portable and remote optoelectronic sensing systems.