Ripple topography on thin ZnO films by grazing and oblique incidence ion sputtering

We have investigated the formation and growth of nano sized ripple topography on ZnO thin films by 10 keV O1+ bombardment at impact angles of 80{\degree} and 60{\degree}, varying the ion fluence from 5{times}10^16 to 1{\times}10^18 ions/cm2. At 800 the ripples are oriented along the ion beam direction whereas at 600 it is perpendicular to the ion beam direction. The developed ion induced structures are characterized by Atomic Force Microscopy (AFM) and the alignment, variation of rms roughness, wavelength and correlation length of the structures are discussed with the existing model and basic concept of ion surface interaction.