Study On The Fabrication, Doping And Characterization Of Zinc Oxide Nanostructure Prepared By Electrochemical Deposition

Zinc oxide (ZnO) nanostructures have attacted more attention because of theirparticular properties in mechanical, optical and electrical fields. A varity oftechnologies have been used to synthesize ZnO nanostructures. A kind of cathodeelectrochemical deposition method was performed to prepare ZnO nanostructures onITO-coated glass substrates in this work, and the mixture of zinc nitrate and potassiumchloride acted as electrolyte. The effect of depositon parameters on the morphlogy,structure and luminescent properties had been investigated by scanning electronmicroscope (SEM), X-ray diffraction (XRD) and photoluminescence (PL)systematically and the growth mechanism had been analysized in details.The results showed that the temperature, electric potential and annealing playedvery important roles in the morphology, structure and luminescent properties of ZnOnanostructures obtained by electrochemical deposition. With the increatment oftemperature, dense ZnO nanostructures with homogeneous size can been obtained,most of which perpendicular to the substrate. However, ZnO nanostructures with lowdensity were prepared at temperature higher than80℃. Therefore the temperature of80℃can be selected to synthesize ZnO nanostuctures with better structure andproperties. Higher potential not only augmented the density of ZnO nanostructures butalso promoted the evolution from nanorods to clusters consisted of nanoneedles whenthe potential was higher than-1.0V. The potential at-1.0V was the most appropriatecondition to prepare ZnO nanostructures with high density and homogeneous size.What’s more, annealing treatment could improve the crystal quality and luminescentproperties of ZnO nanostructures. But the temperature of annealing was very crucial,annealing at300℃could decrease the full width at half maxium of ultraviolet peakfrom319meV to142meV, while higher temperature would increase the defect densityof ZnO, making the luminescent properties poor. The surface state of substrate couldeffect on the morphology, structure and properties of ZnO nanostructures to a greatdegree. Corrosion of substrate with diluted acid would increase the density of ZnOnanostructures and improve its crystal quality and luminescent properties clearly. Atwo-step electrodepositon method had been used to prepare ZnO seeds and then depositZnO nanostructures on the seeds layer, which increased the density of ZnOnanostructures and improve the preferred growth along the c axis. But the time toprepare the ZnO seed layer must be limited within60s.This work also prepared ZnMgO ternary compound with magnesium nitrateacting as the source of magnesium by electrochemical deposition. The results indicated that the doping of Mg changed the morphology of ZnO nanostructures. The dopingamouts of Mg could reach to8.87%with the increase of magnesium nitrateconcentration and the band gap of ternary compound could increase, which proved thatthe band gap can be modulated by doping Mg in ZnO.