Preparation And Optoelectronic Properties Of Cu₂O/ZnO/ITO Heterojunction Film

Cu₂O/Zn O/ITO photovoltaic devices are prepared and studied.The starting point is that the Zn O layer is added to the Cu2 O and ITO.The conduction band and valence band are just between the Cu2 O and the ITO conduction band and the valence band,so that the clear conduction band and valence band can be formed.The Zn O layer acts as a channel to separate the optical carrier,thus reducing the dark current.The main research contents are as follows:First,the growth of Cu2 O films was optimized.Using magnetron sputtering,using quartz glass as the substrate,the sputtering mode,the ratio of oxygen to argon,the sputtering pressure and the sputtering power were prepared by fixing the other parameters as the control.Then X ray diffraction?XRD?,X ray photoelectron spectroscopy?XPS?,atomic force scanning?AFM?,ultraviolet visible spectrometer and Holzer effect are used to study the structure,optical and electrical properties of the film.The performance of the film is studied by comparison of its properties,and the parameters of better performance are found after comprehensive consideration.Growth.The best parameters of the working layer are DC sputtering,oxygen / argon ratio at 6:40,sputtering pressure 1.5 Pa and sputtering power of 70 W.Then,the influence of the thickness of Zn O on the Cu₂O/Zn O/ITO film was studied.It was found that the?200?orientation shifted to?111?orientation when ITO was grown for Cu2 O,and ITO promoted the crystallization of Cu2 O.At the same time,with the increase of the thickness of Zn O,the crystalline quality of Cu2 O is rising.On this basis,the Cu₂O/Zn O/ITO photovoltaic device is prepared,and its photoelectric properties are studied.The device I-V characteristic test shows that the device is in good ohmic contact without the Zn O layer,and the dark current gradually decreases with the increase of Zn O thickness.When the thickness of Zn O is about 380 nm,the device has obvious rectifying effect.The I-V characteristics of the device are divided into three regions,and their ideal factors are 1,0.44 and 1.7 respectively.When irradiated by different light,the current is rising,which is consistent with the photoconductive effect.When irradiated with red light,it can be concluded that the fill factor of heterojunction is 0.021.In addition,we also prepared the multilayer structure film of the Cu₂O/Zn O/ITO conductive film,and studied the effect of the thickness of Zn O on the crystalline quality of the film,and appeared the same rule as that on the ITO glass.Then the Cu₂O/Zn O/ITO conductive film photovoltaic device was fabricated.By testing the I-V characteristics of the device,it was found that the dark current of the device gradually decreased with the increase of Zn O thickness.When the thickness of Zn O is about 380 nm,the dark current is the smallest when the device is-6V,and its value is 0.153 u A.Under different illumination,the photocurrent is larger than the dark current and can satisfy the photocurrent.Finally,the flexible transparent Cu₂O/Zn O/ITO/PET thin films with good structural and optical properties were grown by magnetron sputtering.However,the resistivity of the ITO/PET film prepared under the existing technological conditions is up to 104 ? sq-1,which is far higher than the flexible transparent electrode used at the device level.This needs to be further optimized in the future,in order to greatly reduce the resistivity of the film.