ULTRALOW VALUES OF THE ABSORPTION-COEFFICIENT OF SI OBTAINED FROM LUMINESCENCE

Photoluminescence spectra were measured on homogeneously doped silicon at temperatures of 90 and 295 K. By using the generalized Planck law for the emission of luminescence by indirect transitions, values for the absorption coefficient as small as 10-16 cm-1 have been obtained for photon energies well below the band gap. At higher photon energies, where absorption coefficients can be obtained from transmission, good agreement with literature data is observed. © 1995 The American Physical Society.