Optical properties of CuIn5Se8 and CuGa5Se8 from ellipsometric measurements

摘要: Abstract Spectroscopic ellipsometry measurements were done at room temperature on samples of CuIn 5 Se 8 and CuGa . This allowed determining the real imaginary parts complex refractive index N , dielectric function ɛ absorption coefficient α reflectivity R The energy gap values, E g obtained from fitting numerically second derivative, d 2 ( ω )/d( ) experimental data, ), to analytic critical-point line shapes, are in good agreement with those reported using other techniques. value high frequency constant ∞ for each compound was determined n Sellmeier dispersion formula.