Effect Of Ion Irradiation On The Optical And Electrical Properties Of VO₂ Films

The VO₂ thin film has good thermal induced phase transition property.Insulation-metal transition?MIT?of VO₂ thin film occurs near 68°C,accompanied by abrupt changes in the structure,optical,electrical,and magnetic properties.Due to its remarkable infrared regulation effect in high and low temperature environment,VO₂thin film has attracted the attention of researchers,resulting in a good application prospect in the field of smart window.The effect of infrared control has attracted the attention of the majority of researchers,and it has a good application prospect in the field of smart windows.However,in order to apply successfully the VO₂ thin film in this field,problems such as low temperature deposition,reduction of phase transition temperature,increase of visible light transmittance,and matching of film color with ambient tone need to be solved.Focusing on VO₂ thin films applied in DC reactive magnetron sputtering in the area of smart window,plasma irradiation post-processing technology was used to analyze plasma processing parameters to reduce the phase transition temperature and increase the visible light transmittance.VO₂ thin film samples were made on soda-lime glass substrates by DC reactive magnetron sputtering.Ar/O₂ plasma were used to irradiate the surface of VO₂ thin film,thus changing the parameters of plasma irradiation and studying its influence on the optical and electrical properties of VO₂ thin film,the research contents include:?1?The effect of irradiation power of Ar/O₂ mixed plasma treatment on the optical and electrical properties of VO₂ thin film was studied.In a plasma with an argon-oxygen ratio of 100:50,the surface of the VO₂ film was irradiated at different power densities?0-550 W?.After irradiation,the crystallinity increases and the crystal size increases.The formation of VO₂ clusters on the surface of the film is promoted by low-power?0-400 W?Ar/O₂ plasma treatment.After the power is further increased,V₂O₅crystals are formed.The irradiated samples have significant changes in the order of magnitude of phase transition,phase transition temperature,and thermal hysteresis width.The total spectral transmittance and visible light transmittance both before and after phase transformation are significantly increased with the increase of irradiation power,while the solar energy and infrared regulation rate are slightly weakened.?2?The effect of the ratio of argon to oxygen on the optical and electrical properties of VO₂ thin film was studied.After the sample was irradiated by plasma with different ratio of argon to oxygen,the fixed flow rate oxygen was 50 sccm and with the increase of the argon flow rate,the content of argon plasma in the space increased,and the argon plasma played a leading role in increasing the visible light transmittance.The experimental results show that the increase of the argon flow rate,the change of the order of magnitude of the phase change of the film is not obvious,and the phase transition temperature and the thermal hysteresis width are improved.For example,when the argon-oxygen ratio is 120:50,the visible light transmittance of the sample is significantly improved.When the room temperature is 25°C,the visible light transmittance is increased from 28%to 45%,and the visible light transmittance at high temperature 70°C is increased from 25%to 40%.The external regulation rate weakened slightly from 10%to 5%.However,the phase transition temperature of the sample was increased from 43.5°C to 48°C.?3?The effect of irradiation time in oxygen plasma irradiation on the optical and electrical properties of VO₂ thin film was studied.After the samples were irradiated in oxygen plasma for different times,the VO₂ crystal content in the samples was significantly increased,especially after irradiation for 30 min.The change of plasma irradiation time by fixed oxygen flow has little effect on the order of phase change of the film,and the overall change of phase transition temperature with time shows an increasing trend.Oxygen plasma treatment of VO₂ films at different times also achieved excellent effects of increasing the total spectrum and visible light transmittance,and all samples maintained good solar light energy and infrared regulation.?4?The effect of oxygen flow rate?without argon gas?on the optical and electrical properties of VO₂ thin film was investigated.The experimental results show that different oxygen flow of oxygen plasma increases the V₂O₅ crystallinity in the film,and the VO₂ content in the film first decreases and then increases with increasing oxygen flux.The magnitude of the phase change of the treated film shows a decreasing trend as a whole,the thermal hysteresis width first increases and then decreases,and the phase transition temperature as a whole shows a decreasing trend.If 80 sccm oxygen plasma irradiation,the phase transition temperature is effectively reduced from 51°C to 45°C,the phase transformation temperature modification effect is very significant.In the modification effect of optical properties,the visible light transmittance increased most significantly.After the plasma treatment sample with an oxygen flow rate of 80 sccm,the solar energy regulation rate changed from 11.5%to 7.9%,and the regulation rate of the near-infrared light band changed from 20.5%to 13.6.%,but the visible light transmittance at room temperature 25°C increased from 27%to 43.3%,and the visible light transmittance at high temperature 70°C increased from 22.8%to 40%.