On the excitonic absorption of the epitaxial CdTe thin films

The absorption spectra of CdTe epitaxial thin films of 0.15-12 mum thicknes s deposited onto (0001) mica substrates were investigated in the 1.5-2.8 eV photon energy range. The spectral dependence of absorption coefficient in the temperature range of 78-300 K has been studied. Analysis of absorption coefficient data for 78 K reveals the existence of several excitonic peaks at the energies of 1.583 eV, 1.601 eV and 2.510 eV. The temperature increas e destroyed this fine structure and shifted the absorption edge towards the lower energies. The data are analyzed in connection with the energy band structure of CdTe crystal.