Preparation Of Co-doped ZnO Nanowires And Their Magnetic And Optical Prope Rties

ZnO(oxide zinc) is a kind of important direct band gap semiconductor, which has 3.37 eV band gap and 60 meV exciton binding energy. Zinc oxide not only has the two characteristics, but also has good piezoelectric properties, large specific surface area and other characteristics. These characteristics make it widely used in optoelectronic devices, spin memory and other various fields. Zinc Oxide material has t he good intrinsic properties. The other ions doped into the ZnO make its intrinsic optical properties and magnetic properties optimized, the optimized ZnO materials developed more rapidly and further from the practical application. The main purpose of this paper is to use the two methods, namely simple and controllable solution method and chemical vapor deposition to prepare the ZnO nanowires with large aspect ratio and high purity and ZnO nanowire arrays with vertical substrate. On this basis, use the cobalt element dope ZnO nanowires. The controlled growth methods, structure, optical and magnetic properties of the samples were studied by means of X ray diffraction, transmission electron microscope, X ray photoelectron spectroscopy, superconducting quantum interference device and fluorescence spectrometer. we study the pure ZnO nanowires : 1.The traditional simple and effective solution method was used to prepare ZnO nanowires, which was found to be the key to the growth of the vertical ZnO line array on the substrate. We used two solution methods without seed layer to prepare ZnO and foud that the morphology difference is very big, but there is no difference if we used seed layer. Finally,we know that the seed layer is not only used for the vertical growth of nanowires, but also determines the diameter of nanowires.The diameter of the nanowires prepared by solution method is in the range of 150-250 nm.2. This experiment in the preparation of pure zinc oxide nanowires focus on the effect of the flow rate of Ar, O2 and the trend of pressure during the growth of nanowires. With the increase of Ar flow rate, the length of the nanowires increases, but excessive flow will inhibit the growth of nanowires. With the increase of O2 flow rate, the length of nanowires has been increasing, but the nanowires are becoming the more thick. Pressure changes from 37.5 torr to 75 torr, the length of the nanowires reaches 70 ?m and the aspect ratio of 600 finally. The Co doped ZnO nanowires were prepared on the basis of pure ZnO : 1.In accordance with Zn and Co for 100:1, 10:1, 5:1 and 1:1 ratio of the solution method of doping, its magnetic and luminescent properties were tested. It was found that the coercivity of the ratio of 100:1 reached 242.7 Oe, and the saturation magnetiza tion reached 5.688×10-5 emu, which showed obvious ferromagnetic characteristics. With the increase of the doping concentration, the formation of the other phase makes the magnetic weakened, but the doping concentration will lead to changes in the morphology of ZnO nanowire arrays. Peak position of the optical properties of the main emission peak at 467 nm, 527 nm, 621 nm, emitting green light and red light. And the proportion of the sample with 100:1 is the best. 2.Cobalt doped zinc oxide nanowires were prepared by chemical vapor deposition method with a length of 200?m, the magnetic and optical properties of ZnO nanowires were also tested. It is found that the higher coercivity(450 Oe) is better than that of zinc oxide nano cone, but the crystal quality is not very good, and this kind of structure can not reach the requirement of the preparation of the device. The 361 Oe and the larger length of the sample were obtained by adjusting the conditions. The emission peak was at 385 nm, about 467 nm, the corresponding green emission peak, and the peak width of the visible light emission peak was very large.