Growth temperature dependence of structure in Mg-doped C60 films

Growth temperature and Mg concentration dependence of crystal structure and crystallinity of Mg-doped C₆₀ is studied. The crystal structure of Mg-doped C₆₀ with Mg/C₆₀ molar ratio of 0.3 can be determined as fee structure, same as undoped C₆₀, and the epitaxial film can be grown on mica (001) substrate. Doped Mg atoms affect the adsorption of C₆₀ molecules and suppress re-evaporation, increasing the threshold temperature of re-evaporation from 200°C for undoped C₆₀ to 250°C for Mg-doped C₆₀. It is suggested that doped Mg atoms affect defect formation which induces twins at higher growth temperature. Crystal structure change degradation at the Mg/C₆₀ indicated.