Mechanical and optical properties of titanium dioxide films prepared by pulsed bias arc ion plating
脉冲偏压电弧离子镀TiO2薄膜的力学与光学性能

Uniform and transparent titanium dioxide films were successfully deposited on glass by pulsed bias arc ion plating. Phase structure, surface morphology, microstructure, optical property and hardness of the films deposited at different biases were measured with X-ray diffractometer, atomic force microscope, scanning electron microscope, ultraviolet-visible spectrophotometer and nanoindenter. The results show that the deposited films are amorphous, and the pulsed negative bias plays a key role on the film properties. With the increase of the bias, the film thickness, hardness and elastic modulus change in a similar manner. They all first rise, and then decline. The film thickness reaches a peak in the range from -100 to -200 V, and the latter two parameters reach peak values when the bias ranges from -250 to -350 V. The film deposited at -300 V has atomic smooth surface, Rrms=0.113 nm, and highest refractive index of n550=2.51, which is greater than or equal to the maximum value ever reported. At this bias, the film has the best general properties. The mechanism of how the bias affects film properties is also discussed.