In this work we present a novel thermal oxidation method for the fabrication of ZnO nanowires on CdTe substrates. The results obtained on the modification of their structural and optical properties by using low energy (<5kV) argon ion bombardment are also analysed. Photoluminescence analysis reveals a decrease in the luminescent properties and a shift in the luminescent peak towards lower energies for the sample with nanowires when radiated with ions. However, columnar structures still remain after irradiation. A higher Cd content in the radiated surfaces has also been observed, indicating Cd diffusion enhancement due to the ion irradiation.