Optical NIR VIS VUV constants of advanced substrates for thin film devices
The optical properties of several commonly used single crystal oxide substrates were explored by spectroscopic ellipsometry over a wide spectral range from 0.74 eV to 8.8 eV. The crystals examined are (100) SrTiO3, 0.7% wt Nb doped (100) SrTiO3,(100) (LaAlO3)0.29(SrAl0.5Ta0.5O3)0.7, (011) DyScO3, (100)MgAl2O4, (100)MgO, and (100) LaAlO3, all of which enable epitaxial growth of numerous perovskite type and other optical thin films. An analytic form for the complex dielectric function was derived from ellipsometric data through a physically consistent modeling process. The obtained dielectric spectra were further utilized to calculate the complex index of refraction and absorption coefficient for each substrate material. The absorption spectra and optical band gap were analyzed using Tauc plots. The parameters for reconstructing the dielectric functions are given in detail, allowing for extensive applications of the results of this work. 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