Preparation And Characterization Of Optical And Electrical Properties Of Thin Film Electrodes Of ITO/LaB₆/ITO On PET Substrates

LaB6 nano material is of excellent selective absorption in UV-VIS-NIR. In recent years, LaB6 has become a hot research topic due to its outstanding optical and thermal insulation properties. ITO is the best transparent thermal insulation material at present, and has been widely used in the field of solar cells and flexible transparent conductive films. In this paper, LaB6 and ITO composite films were prepared by magnetron sputtering method. In the first part, plasma pretreatment have been studied to find out the influence on the substrate. Then the optimal sputtering time was studied and the influence of microstructure on optical and electrical properties had been investigated.It was found that PET is the best flexible transparent substrate. When the discharge voltage, discharge current, beam voltage, beam current, accelerating voltage, were kept at 70V,0.15A,0.8kV,12mA and 120V respectively, the optical properties, interfacial properties and contact angle were rising first then down with the pre-treatment time prolonged. And the PET substrate had the highest transmittance, the lowest surface roughness and the best surface wettability when the pre-treatment time was 60s.Growth mechanism of thin films was studied by FESEM, AFM and other methods. Surface bonding strength between thin films was far more than that between films and substrate. Surface roughness rose with the layer of films added, and the surface height increased greatly. ITO/LaB6/ITO thin films had the best microstructure when the sputtering time was 6min,8min,6min respectively.Optical properties showed that when the thin films had the same layers, the transmittance decreased with the thickness of each layer increased. While when the whole thicknesses of different films were all the same, the transmittance increased with the layer added. In addition, electrical properties of the films displayed that with the layer added, the sheet resistance decreased apparently, the carrier concentration increased quickly, and the mobility was almost remain unchanged. Most important, the figure of merit increased sharply with the layer added, and the figure of merit of ITO/LaB6/ITO sandwich thin films was much more than that of ITO/LaB6 thin films, which determined the optimal sputtering time was 6/8/6 min.