Five compositions of Ge14Se86-xTlx (x = 20%, 22%, 23.5%, 26.8%, and 28%) are prepared using the melt-quenching technique. Thin films of thickness d = 15, 30, 60, 90, 120, and 180 nm were deposited using electron-beam evaporation technique. All the films showed a non-Ohmic behavior. At higher range of ambient temperature, the activation energy Delta E-sigma was studied as a function of the coordination number r, average number of constraints N-cos and heat of atomization H-s. Mott's parameters of the system Ge14Se86-xTlx were studied at lower range of temperature. The effect of annealing temperature T-ann on the activation energy was taken in consideration. (C) 2009 Elsevier B.V. All rights reserved.