Research On Co-sputtering Deposition Of MgZnO Alloy Films And Photoelectric Properties

As a third-generation semiconductor material,zinc oxide is favored by researchers for its excellent photoelectric and piezoelectric properties.Using energy band engineering,doping other ion(Al,Mg,Cd,Ga,etc.)into the zinc oxide matrix lattice can make ZnO more widely used in such aspects as ultraviolet detectors,light emitting devices,and solar cells.Theoretically,by incorporating Mg atoms into the matrix lattice of ZnO,the energy band of the obtained MgZnO film can be continuously adjusted in the range of 3.37 e V to 7.8e V.At the same time,since the ion radii of zinc ions and magnesium ions are similar,the doping of Mg into ZnO materials will not cause significant lattice distortion of the materials.It can be better applied to all aspects.Therefore,the research and preparation of MgZnO thin film will be of great significance to the further development and application of this material.The MgZnO film has two crystal lattice structures of hexagonal wurtzite and cubic rock salt.Due to the different preparation process and experimental parameters,the critical point of phase separation of the two structures is still uncertain,but most of them are considered to be between 40-60 at%.The main processes for thin film preparation include metal organic chemical vapor deposition,pulsed laser deposition(PLD),sol-gel,radio frequency magnetron sputtering,etc,while co-sputtering technology is rarely reported.Compared with several other deposition methods,the dual-target co-sputtering technology can more easily realize the deposition and preparation of MgZnO alloy films with any composition ratio,which is suitable for large-area growth.Therefore,studying the co-sputtering method to prepare thin films will provide a brand new idea for the research of MgZnO thin films.In this paper,a co-sputtering process was used to prepare MgZnO ternary alloy films,and the effects of zinc oxide and magnesium oxide target power,different gas atmospheres,and different thermal annealing treatments on the crystallization and optical properties of MgZnO ternary alloy films under the co-sputtering process were studied.It needs to be pointed out that when studying the influence of zinc oxide and magnesium oxide target power on MgZnO film,the magnetron sputtering system will have two variables(ZnO target power and Mg O target power),so in order to control a single variable,To ensure the accuracy of the experiment,we first studied the influence of different sputtering powers on the physical properties of single-target sputtering ZnO films to determine the optimal power of the ZnO target.In the experiment,atomic force microscope was used to characterize the microstructure of the film;X-ray diffraction was used to characterize the crystalline properties of the film;the optical properties of the film were characterized by photoluminescence spectroscopy,and X-ray energy spectrum analysis the content of Mg and Zn in the alloy film.Finally,the optimized conditions were used to prepare MgZnO thin films and MgZnO-based light emitting devices were designed and constructed.Through experiments,it is found that the ZnO film prepared when the ZnO target power is 50 W is the best;in this co-sputtering process,when the target power of Mg O and ZnO are75 W and 50 W respectively,the oxygen-argon ratio is 2:1,the annealing temperature is 700°C,the surface of the MgZnO film is flat and smooth,the roughness is low,and the crystallinity and optical properties are the best.On the basis of the above research,using radio frequency magnetron sputtering and vacuum thermal evaporation technology,an oxy-zinc-magnesiumbased MIS junction light emitting device(Au/Mg O/MgZnO)was constructed.And then the device was subjected to electroluminescence test,the results show that the device achieves relatively pure ultraviolet electroluminescence derived from the MgZnO active layer.