| ITO transparent conductive film is a kind of n-type semiconductor material.Since its discovery,because of its high transmittance in visible light,low emissivity,high reflectivity and good mechanical properties in infrared band,it has been widely used in solar cells,aircraft windshield glass,mobile phone display screen,electromagnetic wave shielding,sensors and other fields.Despite decades of development,there are still some problems that need to be solved,such as the annealing process of ITO transparent conductive films on thermosensitive substrates,resulting in poor performance.In this experiment,ITO transparent conductive films with excellent properties were grown on Corning glass substrates by DC magnetron sputtering,and annealed by periodic "power on-off" current,and high quality ITO transparent conductive films were obtained,which provides a new idea for thermal sensitive substrate annealing.The research work of this thesis is divided into the following two Parts:(1)ITO transparent conductive thin films were prepared on 10 mm × 10 mm × 0.7mm Corning glass by vacuum DC sputtering.The effects of different processes on the properties of ITO transparent conductive films were investigated by controlling the sputtering power,argon pressure,oxygen pressure and annealing time.The experimental results show that under the same process conditions,the crystallinity,transmittance,carrier concentration and mobility of the samples will gradually increase with the increase of sputtering power,and achieve optimal performance at 60 W.However,with the increase of sputtering argon pressure,the properties of the samples will continue to weaken.At the same time,with the increase of annealing time,the light transmittance and carrier concentration of the sample are basically unchanged,but the crystallinity,carrier mobility and conductivity increased gradually,and achieve optimal performance when the annealing time was 3600 s.Finally,with the introduction of oxygen,the crystallinity,light transmittance and conductivity of the samples showed a gradual weakening trend.Finally,when the sputtering power,the argon pressure,the oxygen pressure and the annealing time are set to 60 W,0.5 Pa,0 Pa and 3600 s,respectively,it can meet both the demand of high light transmittance and low resistance,and the average light transmittance of the sample in the visible light range can reach 86.0%,and the square resistance can be as low as 26.0 Ω / sq.(2)Perform vacuum current annealing on the sample and compare it with the thermally annealed sample.The current power is set to 30 W,and the periodic annealing mode of "power on-off" is adopted.In this way,the sample is electrified to generate selfheating in a short time,and then the power is cut off.Thus,the heat is mainly concentrated on the surface of the film rather than transferred to the substrate.It effectively avoids the stress accumulation and microstructure changes in the film due to the heating of the substrate,and improves the utilization rate of energy.Four modes of 0.4 s-9.6 s,0.8 s-9.2s,3.0 s-7.0 s and 5.0 s-5.0 s are set in this experiment.It is found that current annealing can achieve the same performance index as 1h thermal annealing in a shorter time,which greatly optimizes the optoelectronic properties of ITO transparent conductive thin films.After 30 cycles in 5.0 s-5.0 s mode,the average light transmittance in the visible range can reach 86.1%,and the square resistance can be as low as 26.2 Ω / sq. |
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