Uncertainty analysis for the coefficient of band-to-band absorption of crystalline silicon

We analyze the uncertainty of the coefficient of band-to-band absorption of crystalline silicon. For this purpose, we determine the absorption coefficient at room temperature (295K) in the wavelength range from 250 to 1450nm using four different measurement methods. The data presented in this work derive from spectroscopic ellipsometry, measurements of reflectance and transmittance, spectrally resolved luminescence measurements and spectral responsivity measurements. A systematic measurement uncertainty analysis based on the Guide to the expression of uncertainty in measurement (GUM) as well as an extensive characterization of the measurement setups are carried out for all methods. We determine relative uncertainties of the absorption coefficient of 0.4% at 250nm, 11% at 600nm, 1.4% at 1000nm, 12% at 1200nm and 180% at 1450nm. The data are consolidated by intercomparison of results obtained at different institutions and using different measurement approaches.