Photoemission study of the desorption and reaction of C60 and K4C60 films on Si(111) surfaces

X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) have been used to investigate the desorption and reaction of C60 and K4C60 films on Si(111) surfaces. For C60/Si system, C60 multilayers desorb from the surface at 450 K, except the first monolayer. In the case of K4C60/Si system, the desorption of both potassium and C60 begins at 820 K. The potassium atoms are completely removed from the surface at 1000 K, causing the disruption of C60 cage structure and the formations of both SiC and C–Si alloy. Although the C 1s peak due to SiC becomes detectable at 950 K in both cases, the SiC intensity converted by C–Si alloy for K4C60/Si system grows faster at temperatures above 1000 K.