Preparation And Optical Properties Of Transmittance Flexible LaB₆ Films On PET Substrate

nano material is of excellent selective absorption in UV-VIS-NIR. In recent years, LaB6 has been used in plasma cathode and is hoped to be substitute of oxide conductive films such as ITO, ATO and ZAO in the field of transparent insulation material.Less attention has been paid to the preparation and properties of LaB6 target and the studies about transparent flexible LaB6 film have not been reported. In this paper, boron carbide reduction method has been used to prepare high-putity LaB6 powder. The preparation and chemical equivalent of LaB6 target have been studied. The effect of sputtering process on the structure, mechanical properties and optical properties of LaB6 film were studied and the correction among process, microstructure and properties was established.It is found that LaB6 powder with partical size 2.686 μm, purity 99.5139%, residual C 0.0964% was prepared after purified by raising the content of La2O3 in reactants. The introduction of B powder in target is conductive to sintering process, increasing hardness and flexural strength of targets. The correction of B content between target and film was positive. The film LaB6.0627±0.02 was obtained when the ratio of B and La of sputtering target reached 12.5.The thickness and deposition rate decrease with the increase of B content in targets.Sputtering power and argon pressure had significant effect on deposition rate of LaB6 film which rised with the increase of power, increased at first and then decreased with the increase of argon pressure,fell gradually with time. The Crystallinity, density and grain size increased at first and then decreased with the rise of sputtering pwer and argon pressure. TEM results showed that there was nanocrystal with diameter around 10-20 nm and [200] was the preferred growth direction.The hardness and E modulus of LaB6 film increased with the rise of crystallinity, grain size, density and film thickness.The sample deposited at 85 W,0.8 Pa for 60 min achieved the optimal mechanical properties. The transmission peak shifted with the change of sputtering parameters. The selective absorption of LaB6 for ultraviolet and near-infrared light increased with the increase of crystallinity and the reduction of defect concentration. The sample deposited at 75 W,0.8 Pa for 30 min was of the best transmittance and insulation properties.