We have reported a study of the I-V characteristics of Ni/n-GaAs Schottky barrier diodes (SBDs) in a wide temperature range of 60-320 K by a step of 20 K, which are prepared by magnetron DC sputtering. The experimental I-V data of the device quite well obey the thermionic emission model at 300 and 320 K, respectively. The ideality factor and barrier height values have changed by change of the sample temperature, the case has been attributed to the presence of the lateral inhomogeneities of the barrier height. The barrier inhomogeneity has been explained by the Gaussian distribution models of barrier heights suggested by some authors, Y.-L. Jiang et al. [Chin. Phys. Lett. 19, 553 (2002)]; Y.-L. Jiang et al. [J. Appl. Phys. 93, 866 (2003)], and S. Chand, J. Kumar [Appl. Phys. A 65, 497 (1997)]. It has been seen that the SBH inhomogeneity of our Ni/n-GaAs SBD can be well described by Gaussian distribution model suggested by Y.-L. Jiang et al. [Chin. Phys. Lett. 19, 553 (2002)]; Y.-L. Jiang et al. [J. Appl. Phys. 93, 866 ( 2003)] over whole measurement temperature range. Moreover, the modified ln(I(0)/T(2)) versus 1/k(T + T(0)*) plot is obtained using a method developed for T(0) anomaly in the literature. Richardson constant value of 3.37 Acm(-2) K(-2) for n-type GaAs was obtained from the modified Richardson plot.