Exciton Thermoreflectance of GaTe

Thermoreflectance spectra in the exciton region were obtained on the layer compound GaTe. The experimental results can be explained by assuming that the only temperature effect is a shift of the whole structure. The spectra were subjected to a Kramers-Kronig analysis and the changes in the real and imaginary parts of the dielectric constant, induced by the temperature change of the samples, were obtained. At a temperature of 284°K the values of $E_0=1.676\mathrm{}$ eV and $\Gamma =23.5\mathrm{}$ meV are found for the first energy level and the broadening parameter, respectively.