Optoelectronic properties of sol–gel derived ZnO:Co: Effect of Co concentration

•Investigated the effects of Co doping on the optoelectronic properties of ZnO:Co.•Utilizes low cost, solution-based sol–gel deposition process.•Eliminated the commonly observed wrinkle effect in sol–gel deposited ZnO thin films by introduction of Co.•The increase of Co degrades the structure of the ZnO:Co and reduces the optical transmittance.•Electrical properties were investigated using Hall effect measurements and integration into pn junction.

This paper studies the sol–gel synthesis of ZnO:Co thin films as function of Co doping concentration. The derived films were evaluated by using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction measurements, Raman spectroscopy and UV–Vis spectroscopy. SEM images show that the films are smooth with grains size ∼50 nm. It was also found that Co incorporation can decreased the preferential growth in the (0 0 2) orientation and optical transparency. Electrical characterization reveals that the derived films are n-type that can be paired with a p-type material to form rectifying pn junctions.

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