Influence of impurities on the electrical properties of Se₆₅Te₃₅ glasses

A study of the influence of iodine on the electrical transport properties of Se₆₅Te₃₅ glasses is presented. The role played by iodine addition on some structure-sensitive properties as glass transition, crystallization and melting is also investigated by DSC measurements. The addition of iodine leads to an increase of the electrical conductivity and a decrease in the thermopower. In contrast to earlier work, in which n-type conduction in chlorine-doped Se was reported, we observe a positive thermopower in the pure and doped glasses. The results are discussed taking into account the possible interactions between the halogen and the chalcogen atoms.