Investigation On Preparation And Photoelectric Properties Of Zinc Oxide Nanoarrays By Electrodeposition On Seed Layers And Their Heterojunctions

Zinc oxide, as a semiconductor with direct wide band gap, has attracted much attention and also been applied in many fields because of its good optical and electrical performances. In this thesis, a zinc oxide seed layer was prepared on ITO conductive glass and then the zinc oxide nanoarray was electrodeposited on the seed layer to increase the aspect ratio of each nanorod. And a cupric oxide thin film was electrodeposited on the nanoarray to construct a heterojunction, the optoelectric property of which had been investigated.A zinc oxide seed layer was obtained by sol-gel method with spin-coating and annealing steps. Particles of the seed layer were small with the sizes were about 20nm and RMS was between 2-4nm, formed a uniform and dense film successively. Then zinc oxide nanoarrays were prepared on seed layers in zinc nitrate solution by constant potential electrodeposition. The nanoarray has obvious preferred orientation in (001) plain, the band gap is about 3.30eV while there are little defects in it. The diameter of each nanorod was 40-70nm, and the length could be easily controlled.The electrochemical behavior of the initial zinc oxide growth on the seed layer acted as the traditional instantaneous model, which presented that the nanoarray grew up with the seed layer particles as the nuclear in fact. And the process on ITO is close to a progressive nucleation process. In the process of electrochemical growth, the concentration of zinc nitrate played an important role in the nanorods formation. Potassium chloride acted as supporting electrolyte as well as a complex agent which have great effect on the vertical growth of the zinc oxide nanorods.In copper sulfate alkaline solution complexed with tartaric acid, cupric oxide thin films were prepared by constant potential electrodeposition on zinc oxide nanoarray to construct a zinc oxide nanoarray/cupric oxide heterojunction. The optoelectric property was measured, and the open circuit voltage was 193mV while the power conversion efficiency was 0.01% after annealing, which showed that this structure had a good application potential.