Dependence of the spectra of charge carriers on the concentration of defects in silver telluride

A change in the band gap as a function of the concentration of electrically active defects in silver telluride has been considered. It has been found that the electronegative and electropositive defects lead to an increase and a decrease in the band gap , respectively. It has been revealed that, in Ag2Te with Te concentrations of higher than or equal to 0.75 at %, the band gap has an unusually low value (similar to 0.008 eV). In the case where the band gap is characterized by the temperature dependence E > (g) = (0.008(-7) x 10(-5) T) eV, at T > 100 K, there is a gapless state. Owing to the changes in the concentration of electrically active defects, silver telluride can exhibit n- and p-type conductivities, unlike other silver chalcogenides (Ag2S and Ag2Se).