Influence of Fe doping on nanostructures and photoluminescence of sol–gel derived ZnO

The doping of Fe (0.5, 2, and 50 mol%) in ZnO was performed using sol–gel process, which led to noteworthy alterations in the microstructure, phase formations and optical properties. Nanoparticles (20–50 nm) with euhedral shape morphology and aggregated nanowires (20–30 nm diameter) are observed at 2 mol% Fe doping, whereas well developed and facetted nanoparticles (50–100 nm), nanowires (∼60 nm diameter) and ultrafine particles (2–5 nm) are seen at 50 mol% Fe doping. The hexagonal-ZnO was present as the dominant phase with the traces of cubic-ZnFe2O4 up to 2 mol% Fe, while at highest 50 mol% Fe doping, ZnFe2O4 was the observed prominent phase, which is also responsible for the observed violet (412 nm, 3.0 eV) and blue emission bands (468 nm, 2.65 eV and 440 nm, 2.82 eV) together with quenched orange (632 nm, 1.96 eV) and green (523 nm, 2.37 eV) luminescence.