Forming And Photoeletric Propertices Of TiO₂/CdSe/Metal Composite Films

As a renewable clean energy,solar energy can be converted into electric energy and chemical energy,solving the problems of energy shortage and environmental pollution.TiO₂ has widely used as conversion materials for solar cells and photo catalysis owing to the stable chemical performance,abundant resources,high-efficiency and non-toxic.However,TiO₂ is a wide bandgap semiconductor?anatase 3.0 eV,rutile 3.2 eV?,only absorbing the ultraviolet light?5% of the sunlight?.Meanwhile,the rapid recombination velocity of photoelectrons and vacancies causes that quantum efficiency drops,limiting the practical application in visible light.In this paper,the TiO₂ nanotube arrarys have been prepared and modified through semiconductor coupling and metal deposition,aiming to enhance the utilization of solar energy and separation efficiency of electron hole pair.?1?TiO₂ nanotube arrays?TNTs?were prepared in Ti-base by anodic oxidation.Being annealled at different temperature,CdSe films were deposited on TNTs using cyclic voltammetry.The crystal structure,morphology,photoelectric properties of heterojunction films were investigated by X-ray diffraction?XRD?,field emission scanning electron microscopy?FESEM?,ultraviolet-visible spectrophotometer and electrochemical workstation.Theresults show that TiO₂ nanotube arrays annealled at 450? for 2h is most beneficial to the deposit of CdSe nanoparticles.CdSe Nanoparticles with cubic crystal disperse uniformly.The photocurrent density of heterojunction reaches to3.84mA/cm2.?2?Cd Se nanoparticles were deposited on TNTs using cyclic voltammetry.Au was deposited on the CdSe/TiO₂ heterojunction films by magnetron sputtering using Au as a target source and TiO₂/CdSe/Au composite films were prepared.The influence of sedimentary sequence between Cd Se with Au to photoelectric properties of TiO₂/CdSe/Au composite films was studied.The results show that TiO₂/CdSe/Au composite films consist of TiO₂ with anatase phase,CdSe with cubic crystal and Au with face centered cubic structure.Composite films display optical photoelectric properties and reach to6.05mA/cm2 when Au deposites on the surface of TiO₂/CdSe films.When the Au is located at the middle of TiO₂ and CdSe,photoelectric properties of composite films drop.The analysis establish that noble metals modifying semiconductor comply with the mechanism of Schottky contact.?3?Cd Se nanoparticles were deposited on TNTs using cyclic voltammetry.Al was deposited on the Cd Se/TiO₂ heterojunction films using physical vapor deposition and TiO₂/CdSe/Al composite films were prepared.The influence of sedimentary sequence between CdSe with Al to photoelectric properties of TiO₂/Cd Se/Al composite films was studied.The results show that TiO₂/CdSe/Al composite films consist of TiO₂ with anatase phase,CdSe with cubic crystal andAl.Composite films displays the optical photoelectric properties and reach to6.05mA/cm2 when Al is located at the surface of TiO₂/CdSe.The analysis suggest that low work function metals modifying semiconductor abide by the mechanism of Ohmic contact.