STM observations of Ag-induced reconstruction of C-60 thin films

By depositing Ag on C-60 films grown on the Si(111)7x7 surface, interaction s between Ag and C-60 were studied by using scanning tunneling microscopy. Significant morphology changes were observed after the deposition at room t emperature of Ag onto multilayer C-60 films. In such films, Ag clusters bon ded to C-60 molecules, as well as layered C-60 structures with nanometer si ze were observed. A few possible mechanisms for the Ag-induced reconstructi on of C-60 films are discussed. Based on the experimental results and analy sis, we propose that there exits a critical size for the Ag clusters. For A g clusters greater than this critical size, charge transfer from Ag to C-60 will occur; while for Ag clusters smaller than this, only weak van der Waa ls type interactions exist between Ag and C-60.