Abstarct: In this theoretical research work, we have investigated the temperature dependence of current-voltage (I-V) characteristics in some Schottky diodes including mextal-semiconductor (MS) contacts in Au/n-GaN structure (grown by two different methods) and mextal-oxide-semiconductor (MOS) contacts in Au/SiO2/n-GaAs structure baxsed on thermionic emission theory and its extended version. In low-voltage range, the applied analysis for finding the potential barrier height and the ideality factor is baxsed on two approaches: the first one is baxsed on the flat-band theory at the interface considering various potential barriers at different contact points due to the effect of the image forces; and the second one which is baxsed on inhomogeneous lateral potential barriers at different points of the interface due to surface roughness and the presence of crystal defects. In the studied samples it was revealed that by increasing the device temperature the ideality factor has a decreasing trend and the potential barrier height has an increasing trend. Through data analysis we found that in the first theory the thermal coefficient variations of the potential barrier is well compatible with that of the semiconductor band gap; and in the second theory, considering a Gaussian distribution for the lateral potential heights, the standard deviation (showing how much a quantity is distributed around the mean value) is an important parameter. Meanwhile we found a well compatibility between the values of the effective potential barrier in the first theory and the mean potential barrier (the peak Gaussian distribution) in the second one. In addition it is found that the second theory provides not only the preliminary theory results, but also it successfully predicts the effective Richardson coefficient in these junctions.