Nanocomposite (nc) ZnO-SiOx thin films were grown using rf magnetron sputter deposition technique and post-deposition annealing at 750 degrees C. These films were irradiated with 750 keV Argon ions at fluences in the range from 1 x 10(15) to 1 x 10(17) ions/cm(2), using Low Energy Ion Beam Facility (LEIBF) at IUAC. Xray diffraction (XRD) patterns of the as-deposited irradiated films show decrease in intensity of ZnO peaks relative to pristine film. Fourier transform infrared (FT-IR) spectroscopy measurements of the asdeposited irradiated films indicate the breakage of Zn-O, Zn-O-Si and Si-O-Si bonds in them, which is substantiated by FT-IR measurements of 750 degrees C annealed films that were irradiated at a fluence of 10(16) ions/cm(2). Photoluminescence (PL) measurements show drastic decrease of visible PL emission from as-deposited irradiated films. Current Voltage (I-V) measurements show decrease in surface resistance of irradiated films by three orders of magnitude. The results suggest that 750 keV argon ion irradiation of nc ZnO-SiO, films has resulted in the formation of non-radiative defects in ZnO phase and damage in SiOx, and amorphization in Zinc silicate phase. These results are explained on the basis of the dominant energy loss mechanism of low energy ions in materials. (C) 2015 Elsevier B.V. All rights reserved.