The reflectivity spectra of Cd1-xCoxTe single crystals

The reflectivity spectra of Cd1-xCoxTe (x=0, 0.003, 0.005) single crystals were obtained in the 2 similar to 6 eV photon energy range at room temperature. The spectra revealed distinct structures at energies of the E-1(Lambda(4,5)(v) --> Lambda(6)(c)), E-1 + Delta(1)(Lambda(6)(v) --> Lambda(6)(c)), and E-2(X-7(v) --> X-6(c)) critical points. The remarkable blurring of the spectra was not observed up to a cobalt content x=0.005. The E-1, E-1 + Delta(1), and E-2 energies decreased with composition x, which may be due to not only the interaction of CdTe bands and Co 3d levels but also the alloying effect.