Thermoreflectance spectroscopy of CdGa2Te4 -: art. no. 045218

Thermoreflectance (TR) spectra of the defect-chalcopyrite-type semiconductor CdGa2Te4 have been measured in the 1.4-5.5-eV photon-energy range at T=40-300 K. The experimental TR spectra reveal distinct structures at energies of the E-1-E-8 critical points (CP's). These CP's are successfully assigned to specific points in the Brillouin zone. The temperature variation of the CP parameters has also been determined and analyzed using the Varshni equation and an analytical four-parameter expression developed for the explanation of the band-gap shrinkage effect in semiconductors.