Tailoring energy band gap and optical absorption of Cd doped MnTe2

Abstract We have used the full potential-linearized augmented plane wave method to predict the structural, electronic and optical properties of Mn1-xCdxTe2 compounds (x = 0, 0.25, 0.50, 0.625, 0.75, 0.875, 0.968, 1.0). The bands near the Fermi energy level are predominantly contributed by the Mn-d and Te-p states. A transition from metallic to semiconducting nature can be observed with increasing doping (Cd) concentration. The DOS and energy bands of these materials reflect semiconducting nature of CdTe2, with an energy band gaps of 0.71 eV, that has been enhanced (0.95 eV) close to the experimental report of 1.08 eV by employing mBJ functional. From the study of optical properties, it is found that CdTe2 and MnTe2 both have very high absorption coefficient, exceeding 104 cm -1. As the Cd concentration increases in the Mn site, the refractive index of the material decreases and the material becomes opaque in the lower frequency range.