The Growth And Optical Properties Of Controllable Zinc Oxide Nanowires

Zinc oxide (ZnO)one-dimensional nanostructures have excellent performance as a widebandgap direct-bandgap semiconductor: including large forbidden band width(3.37 eV),exciton binding energy up to 60 meV at room temperature,and almost no ultraviolet light sensitivity in the visible light range.The response and other characteristics have become ideal materials for solar-blind photoelectric detection.Therefore,the study of one-dimensional nanostructures of ZnO not only contributes to the application of ultraviolet photodetectors,but also has an important guiding role in studying the optical properties of ZnO nanowires.Based on the hydrothermal method of growing ZnO nanowires,this paper has grown a nanowire array with a controllable diameter in the [0001] direction by analyzing the influence of different growth factors.On this basis,the optical properties of hydrothermally grown ZnO with different diameters are analyzed and measured;it provides an experimental basis for the final realization of the preparation of ultraviolet detectors from ZnO nanowires with different diameters.In this paper,the hydrothermal method is selected as the synthesis method of onedimensional ZnO nanowires,focusing on analyzing the growth status of ZnO nanowires by controlling the precursor concentration,reaction time,reaction temperature,p H value,etc.,and obtaining ZnO nanowires with controllable diameter by optimizing growth parameters Line array;use scanning electron microscope(SEM)and atomic force microscope(AFM)to characterize ZnO one-dimensional materials.At the same time,the effect of the seed layer on the growth of ZnO nanowires was studied through different annealing temperatures;finally,ZnO nanowire arrays with diameters of about 50 nm,100nm,150 nm,180nm and 200 nm were prepared,and they had good orientation on the surface of [0001].Based on the hydrothermal method to prepare ZnO nanowire arrays with different diameters,the ZnO nanowires were characterized by spectrometer,X-ray diffraction and other means.The experiment measured the ultraviolet luminescence of the ZnO nanowire arrays grown on the ITO substrate as the diameter increased.The peak is red-shifted,the absorption peak of the array with a diameter of about 50 nm corresponds to a wavelength of about 379nm;when the diameter is 200 nm,the corresponding wavelength of the absorption peak is 384nm;compared to the intrinsic bulk ZnO material,there is a significant red-shift phenomenon at368 nm.At the same time,absorption peaks were observed in red light and blue-green light,but there was no obvious red shift.In addition,it was observed by photoluminescence(PL)that as the diameter of the ZnO nanowires increased,the intensity of ultraviolet luminescence decreased.On the basis of preparing ZnO nanowires with controllable diameter based on hydrothermal method,ITO-ZnO-PEDOT-Ag structure ultraviolet photodetector is formed by suspension coating of PEDOT and evaporating Ag electrode;by comparing three kinds of devices with different ZnO nanowire diameters The measurement found that the photoresponse time of the ZnO ultraviolet photodetector with a diameter of 50 nm is shorter,the rise time is about 7.1s,and the decay time is about 3.5s;at the same time,the ratio of photocurrent to dark current can reach 270.Photocurrent generation is also detected without applying external voltage.The red shift phenomenon of absorption wavelength of ZnO nanowire arrays with different diameters can also be used to prepare high-precision fixed-wavelength ultraviolet detectors,which provides a reference for high-precision applications of ultraviolet detectors.