Photoacoustic determination of low absorption coefficients in CdI2 layered semiconductor

Photoacoustic spectra in thin samples of CdI₂ layered semiconductor have been measured in the region of energies near the fundamental energy gap. By means of this technique it was possible to obtain the spectrum of the low values of the absorption coefficient in the range between 3.12 and 3.26 eV, where the absorption coefficient varied from 5 to 100 cm^-1. The experimental results are sound with respect to the indirect nature of the optical gap of the CdI₂.