In-situ observation of ion beam-induced nanostructure formation on a Cu(In,Ga)Se2 Surface

We report a phenomenological study of Cu(In,Ga)Se2 (CIGS) dots and their morphological transition into nano‐ridge shapes induced by application of a focused ion beam (IB) to CIGS film. Real‐time observations of nano‐structure evolution during IB irradiation were obtained by recording sequential images at various ion energies of 1 to 30 keV. We observed that as irradiation time increased, the dots became larger and developed elongated ridge structures under continuous sputtering. This transition process was induced by a combination of the Ostwald ripening processes and cluster diffusion. Compositional analysis revealed that the nano‐dots changed from pristine CIGS to Cu‐rich CIGS. The Ga content of the dots was also found to increase due to sputtered implantation, while levels of In and Se decreased. Copyright © 2012 John Wiley & Sons, Ltd.