Temperature effect on the electronic structure of AlN - art. no. 113105

The temperature dependence of the optical reflectance spectra for aluminum nitride was measured on a high-quality single crystal with synchrotron radi ation. The dominant structure due to the interband transition was observed at photon energy of 6.16 eV at room temperature. With decreasing temperatur e, the energy positions of the dominant structure in the reflectance spectr a shift towards higher energies and this energy shift was found to be well described by the Bose-Einstein expression with the parameters obtained by a bsorption spectra measurements. The feature due to crystal-field and spin-o rbit splitting of the valence was also observed around the interband transi tion, especially prominent at low temperatures.