We have fabricated an Au/perylene-monoimide (PMI)/n-Si organic-on-inorganic Schottky device by spin coating of PMI solution on an n-Si semiconductor wafer. Current-voltage (I-V) measurements on the device in the temperature range of 75-300 K were carried out. An abnormal decrease in the experimental barrier height φB and an increase in the ideality factor n with a decrease in temperature have been observed. This behaviour has been explained on the basis of thermionic emission theory with a double Gaussian distribution of the barrier heights due to the barrier height inhomogeneities. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.