Effect Of Doped Element On Structure And Properties Of ZnO Thin Films Prepared By Oxidation Method

Zinc oxide(ZnO)is a direct wide bandgap semiconductor material with a bandgap width of 3.40eV and exciton binding energy reach up to 60 meV at room temperature,and has excellent physical properties.In addition,ZnO has a wide range of raw materials,low cost.It has wide application prospects in optoelectronics,thermoelectric,dilute magnetic semiconductors,pressure sensors and other fields.As a typical oxide semiconductor,as same as other types of semiconductors,ZnO need to change the structure by doping to improve its performance.Although ZnO-based semiconductor thin films have been extensively studied,they have not been widely used.An important reason is not effectively control doping,improve the microstructure,enhance its performance,up to the standard of the practical application.Therefore,it is important to study the effect of different doping conditions on the structure and properties of ZnO thin films by controlling the doping of ZnO thin films by changing the experimental conditions.In this paper,ZnO thin films were prepared by oxidation method,Preparation methods(Magnetron sputtering,thermal evaporation),Deposition conditions(Growth pattern,composition),Oxidation conditions(Oxidation modes,oxidation temperatures,oxidation times,oxidation atmospheres,high magnetic field(HMF))were investigated.And finally achieve the purpose of controlling the microstructure and properties of ZnO thin films by doping.For the Co doped ZnO(Co:ZnO)thin films,the effects of co-layer deposition,bilayer deposition,multilayer deposition and HMF on the structure and magnetic properties of the films were investigated.The effects of constituents and oxidation conditions,such as oxidation temperature,oxidation time and oxidation conditions about the structure and thermoelectric properties of the films were investigated.For the N doped ZnO(N:ZnO)thin films,the effects of oxidation conditions,such as oxidation mode,temperature and time on the structure and conductivity of N:ZnO thin films were investigated.Finally,the way and mechanism of the doping of ZnO thin films were determined,and the following conclusions were obtained:For the Co:ZnO thin films,the co-layer films have the lowest surface roughness,and one order of magnitude lower than that of the other two growth modes.After oxidation,the magnetization of co-layer films is bilayer deposition a modes,and 15%higher than multilayer deposition.The HMF inhibits the formation of the second phase such as CoO during the oxidation process.After applying the HMF,the saturation magnetization of the film increases more than 50%and the coercivity decreases by about 27%.The saturation magnetization of the film increases about 50%,and the coercivity decreased by about 32%.The saturation magnetization of multilayers increased by more than 650%and the coercivity decreased by nearly 45%.For Al:ZnO thin films,compared with Al evaporation temperature ia 1050?(Al 1050)and 1070?(Al 1070),the surface roughness of which evaporation at 1030?(Al1030)thin films is more than 40%lower than the other two types films.The thin film of Al1030 oxidation at 500? for 3h is formed thin films with ZnO as the main phase,and has obvious semiconducting properties.The surface roughness of Al1030 thin film precursor after oxidation at 500? for 3 h under 0.12 MPa pure O2 atmosphere is about 35%lower than that of 0.10 MPa(atmospheric pressure)in pure O2 atmosphere,and the power factor is one order of magnitude higher than that in pure O2 condition under 500? the best performance of the oxidation film.For N:ZnO thin films,the oxidation modes showed that the surface of the air-cooling film was flat,and the transmittance was similar to that of other oxidation methods.The results show that the N:ZnO films have p-type conductivity at 300? for 60 min,but there are still some Zn and Zn3N2 in the films.The visible light transmittance is about 40%,and the near-infrared light transmittance was only about 50%,and the oxidation temperature was selected as 400?.For the oxidation time,the number of large particles on the surface of the film increased first and then decreased with the oxidation time prolonged.At 400 ?,the surface particles were oxidized for 60 min and the transmittance of the near-infrared region was 90%,but the conduction characteristics of the films is all n-type.