Study of the band-gap energy of radiation-damaged silicon

The transmission of silicon crystals irradiated by 24 GeV/c protons and reactor neutrons has been measured for photon energies, $E{\gamma}$, between 0.95 1.3 eV. From the data absorption coefficient ${\alpha}$ is calculated, from ${\alpha}(E_{\gamma})$ fluence dependence band-gap energy, $E_{gap}$, energy transverse optical phonons, $E_{ph}$, determined. It found that within experimental uncertainties about 1 meV neither $E_{gap}$ nor $E_{ph}$ depend on up to maximum $1 \times 10^{17}$ cm$^{-2}$ measurements. value agrees with generally accepted value, if an exciton-binding 15 assumed. A similar agreement $E_{ph}$. For extraction second derivative $\sqrt{{\alpha}(E{\gamma} )}$ smoothed a Gaussian kernel used.