The XPS investigation on the PC films irradiated by MeV Cn+ (n = 1–5) cluster ions

Irradiation of MeV Cn+ (n = 1–5) cluster ions onto polycarbonate (PC) films was performed and the surface chemical structure was analyzed in detail by X-ray photoelectron spectroscopy (XPS). The irradiation condition was 0.6 MeV/atom and atomic dose of 5 × 1012 ions/cm2. The results show that the ratio of C 1s to O 1s (C/O) of PC surface irradiated by C cluster with the same atomic energy and dose gradually decreased with increasing of cluster size then tended to a saturation. It indicates that the oxygen and carbon atoms contained in PC films were selectively sputtered by carbon cluster ions. As to the ratio of C/O of PC films irradiated by individual C decreased linearly with increasing of projectile energy. XPS results show that ion beams induce the change of chemical element ratio, restructure of near surface of PC and formation of new type of bond.