采用脉冲激光沉积法(PLD)在不同Si(100)衬底温度下制备了La_0.5Sr_0.5CoO₃(LSCO)导电金属氧化物薄膜.X射线衍射(XRD)分析表明,随着衬底温度升高LSCO薄膜的结晶质量增加,在650℃和700℃下制备的薄膜是具有单一钙钛矿结构的多晶薄膜.通过椭圆偏振光谱仪测量了400～1100nm波长范围内该导电金属氧化物薄膜的光学性质,采用双Lorentz振子色散关系及三相结构模型(Air/LSCO/Si)拟合获得了薄膜的光学常数.结果表明,薄膜的折射率随着衬底温度的升高而减小,然而在可见-近红外波长范围内消光系数随着衬底温度的升高而增大.这主要与薄膜的晶化质量和导电性能有密切的关系.

pulsed laser deposition; La0.5Sr0.5CoO3 films; spectroscopic ellipsometry; optical constant; (LSCO) conductive metal oxide films were prepared on Si (100) suhstrates under different growth temperatures by using pulsed laser deposition (PLD). X-ray diffraction (XRD) analysis shows that the crystallinity of the LSCO films increases with the increase of substrate temperature, and the films deposited at 650℃ and 700℃ are polycrystalline with a single perovskite phase. The optical properties of the LSCO films were measured by spectroscopic ellipsometry in the wavelength range of 400 - 1100nm. Double Lorentz oscillator dispersion relation and a three layer model (Air/ LSCO/Si) were used to fit the optical constants of the films. The results show that the refractive index of the LSCO films decreases as the substrate temperature increases. Extinction coefficient of the LSCO films increases as the substrate temperature increases in the visible and near-infrared wavelength range. It is found that the crystallinity of the films and conductivity are mainly responsible for these phenomena.