The current-voltage characteristics of graphene/n-type Si (n-Si) Schottky diodes with and without annealing were measured in the temperature range of -120 to 30 degrees C and analyzed on the basis of thermionic emission theory. It is found that the barrier height decreases and the ideality factor increases with the decrease measurement temperatures. Such behavior is attributed to Schottky barrier inhomogeneities. It is shown that both the barrier height and the ideality factor can be tuned by changing the annealing temperature. Through the analysis, it can be suspected that a SiOx layer at the graphene/n-Si interfaces influences the electronic conduction through the device and stoichiometry of SiOx is affected by annealing treatment. In addition, both Schottky barrier inhomogeneity and the To effect are affected by annealing treatment, implying that stoichiometry of SiOx has a noticeable effect on the inhomogeneous barriers of graphene/n-Si Schottky diodes. (C) 2014 Elsevier B.V. All rights reserved.