We have investigated the temperature dependence of the current-voltage (I-V) characteristics of Au/a-Si:H Schottky structures using different back metal ohmic contacts (At, Cr, Mg or combination of Mg/Sb). I-V characteristics were measured in a wide temperature range (from 145 to 425 K) to find out the temperature dependence of the ideality factor, barrier height and series resistance for the different metal contacts used. We have also calculated the modified Richardson constant and barrier height from the plot of thermionic emission saturation current as a function of temperature. (C) 2006 Elsevier Ltd. All rights reserved.