- The optical characterization of transparent conductive thin films is demonstrated. The
basics of transparency and conductivity, as they relate to transparent conductor research, are
explained. A functional model of the reflectance and transmittance of a sample film, including
interference fringes, is derived from the Fresnel electric field amplitude coefficients. The
wavelength-dependent refractive index is determined by analysis of the interference fringes. Two
methods for determining the absorption coefficient spectrum have been shown and compared.
The absorption coefficient spectrum is used to determine the magnitude and the direct/indirect
nature of the energy gap of the material. The significance of the diffuse spectral components of
both transmittance and reflectance, with respect to analyzing the energy gap, is also demonstrated.