Shape of the silicon absorption coefficient spectrum near 1.63 eV.
We report high precision, high spectral resolution measurements of the absorption coefficient of silicon in the spectral region from 1.61 to 1.65 eV. Our data show a smooth absorption spectrum with no discernable features in this spectral region where structure has been reported previously. Our data and analysis suggest that the second indirect transition in silicon has yet to be detected in absorption coefficient spectra.