Preparation And Research Of ITO/AZO Transparent Film Thermocouple

Compared with the traditional film thermocouple,transparent film thermocouple has minimal optical disturbance when measuring temperature.In this paper,a transparent film thermocouple based on indium tin oxide(ITO)and zinc aluminum oxide(AZO)was prepared,and the transmittance and thermoelectric output of thermocouple were studied.In this paper,ITO and AZO films with high transmittance,high stability and low resistivity were selected as the electrode materials of transparent film thermocouple.ITO film was prepared by DC pulsed magnetron sputtering.It was found that in the process of preparing ITO film by DC pulsed magnetron sputtering,with the increase of reverse time from 0 to 4.0 ?s,ITO films gradually changed from non to(100)preferential orientation.Meanwhile,the band gap and carrier concentration of ITO film increased from 3.92 to 4.15 eV,and 2.93×1020 to 4.25×1020/cm3,respectively.The carrier mobility decreased from 31.58 to 23.89 cm2/Vs.The voltage waveform of DC pulsed power supply unit during sputtering was recorded by the digital oscilloscope.It was found that with the increase of reverse time from 0 to 4.0 ?s,the sputtering power displayed on the front panel of power supply unit was the average power in one cycle.While the maximum instantaneous power of the power supply increased gradually with the increase of reverse time.When the reverse time was 4 ?s,the maximum instantaneous power of the power supply was 2.09 times of the average power displayed on the front panel.With the increase of maximum instantaneous power of power supply,ITO grains changed from equiaxe to columnar grains,which improved the photoelectric properties of ITO film.In the process of magnetron sputtering,the stepping motor was used to keep the substrate moved in a straight line,with rotating.By this way,the thickness of film thermocouple was more uniform.The transparent film thermocouple was fabricated on the slide substrates by mechanical masks.Then,the transparent film thermocouple was calibrated statically.The results showed that the transmittance of film thermocouple was over 87.84%in visible range.EMF-temperature curve of transparent ITO/AZO film thermocouple was linear in the range of 0-170?.The existence of SiO2 protective film inhibited the diffusion of oxygen element in the heating process.So,ITO/AZO film thermocouple had great repeatability in calibration.The crystal of ITO film changed from equiaxed crystal to columnar crystal which improved the carrier concentration of ITO film.For this reason,with the increase of reverse time from 0 to 4?s,the thermal EMF and contact EMF of ITO/AZO film thermocouple were both improved,which improved Seebeck coefficient of ITO/AZO film thermocouple from 6.2 to 40.8 ?V/K.