Determination of interference-free optical constants of thin films

A computational procedure has been developed for the accurate determination of interference-free optical constants (refractive index, n1 and extinction coefficient, k1) of thin solid films from reflectance (R) and transmittance (T) measurements. By using (1−R)/T function and a successive refinement loop, error in calculation of the absorption coefficient (α) has been minimized. The method has been successfully used for the determination of optical constants and band gap of CuIn1−xGaxSe2 and Sb2S3 thin films.