Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Metallurgical Engineering

Research into nanomaterials has become more and more popular because of their unique properties compared to bulk materials. Amongst various functional materials, zinc oxide (ZnO), with a direct electron energy band gap of 3.34 eV at room temperature, is an important optoelectronic material with an intrinsically n-type semiconducting property. However, to form a p-type ZnO semiconductor is still a challenge. Copper oxide , compared to ZnO, has a much smaller band gap, 1.2 eV, and shows an intrinsically p-type semiconducting property. It has been suggested that when Cu₂O is alloyed with ZnO properly, a p-n semiconductor heterojunction can be formed to be utilized in solar cell and gas sensor applications. In this thesis, ZnO/Cu₂O core-shell nanowire arrays have been successfully fabricated by a simple two-step process. ZnO nanowire arrays were first grown by the anodization method using Zn foil substrates. Copper then was deposited on as-grown ZnO nanowire arrays by chemical bath deposition method. ZnO/Cu₂O core-shell nanowire arrays have exhibited better photoelectrochemical efficiency in visible region as compared to the pure ZnO nanowire arrays, which suggests that ZnO/Cu₂O core-shell nanowire arrays have strong potential as nanoscale building blocks in solar cells and light emission devices

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