The forward and reverse bias current-voltage (I-V) characteristics of Au/n-GaAs/GaAs have been measured in the temperature range of 79-400 K. The effects of density of interface states N(ss) and the series resistance R(s) of structures on the electrical characteristics are investigated as a function of temperature. While the zero-bias barrier phi(Bo) decrease, the ideality factor n increases with a decrease in temperature, the changes are quite significant at low temperatures. Experimental results show that the R(s) and N(ss) cause non-ideal behavior on I-V characteristics. The R(s) is significant especially in the downward curvature of the forward bias I-V characteristics, but the N(ss) are significant in both the linear and non-linear regions of the I-V characteristics. The downward concave curvature of the forward bias I-V curves at sufficiently high voltages has been attributed to the presence of R(s), apart from the N(ss) that are in equilibrium with the semiconductor. The high value of the ideality factor n and the Schottky barrier height phi(Bo) of these structures were attributed to the presence of an interfacial insulator layer between metal and semiconductor. The density of interface states distribution profiles (N(ss)) as a function of (E(c)-E(ss)) was obtained from the forward bias I-V measurements by taking into account the bias dependence of the effective barrier height phi(e) and ideality factor n at different temperatures for the sample on the order similar to 10(13) eV(-1) cm(-2). In addition, the values of n, phi(Bo) and R(s) of these structures have been obtained at each temperatures using Cheung's functions.