Spectroscopic ellipsometry applied to phase transitions in solids: Possibilities and limitations

The possibilities of in situ spectroscopic ellipsometry applied to phase transitions investigation in oxide thin films and crystals are examined in this work, along with the use of various parameters calculated from ellipsometric data (band gap energy E_g, refractive index n and surface roughness) together with the directly measured main ellipsometric angles ψ and Δ, for the detection of phase transitions. The efficiency of spectroscopic ellipsometry on "surface" phase transition and its sensitivity to surface defects are also demonstrated.