Temperature dependence of the fundamental absorption edge in CuInTe2

The temperature dependence of the energy gap $E_G$ and the binding energy $R_x$ of free excitons in single crystals of ${\mathrm{CuInTe}}_{\mathrm{2}}$ have been calculated using Elliot’s model. The samples were prepared by the method of tellurization of stoichiometric Cu and In in liquid phase and the vertical Bridgman technique. The value of $R_x$ around 4 meV agrees quite well with that deduced from the effective mass approximation. The variation of $E_G$ with temperature is compared with the empirical model proposed by A. Mannogian and J. C. Woolley [Can. J. Phys. 62, 285 (1984)]. The estimated value of the Debye temperature is in agreement with ${\Theta }_D$ =$\text{191.4\hspace{0.17em}}\mathrm{K}$ reported from specific heat measurements.