Possible detection of doping atoms in C60 solid clusters by high-resolution electron microscopy Original Research Article

Possibility of direct detection of doping atoms in C60 solid clusters by high-resolution electron microscopy (HREM) was investigated by using calculated residual indices (RHREM) and difference images. HREM images of C60 doped with nitrogen and rubidium atoms were calculated as functions of accelerating voltage of microscope, crystal thickness and defocus values. Difference images of N@C60/C60 and RbC60/C60 showed N and Rb atomic positions clearly at high accelerating voltage and large crystal thickness. RHREM values of RbC60 are strongly dependent on accelerating voltage and crystal thickness, which would be due to the dynamical diffraction effect of Rb atoms. Defocus values also influence the RHREM values, and the Scherzer defocus would be the best for atomic detection. The present work indicates that the doping atoms at the inside and interstitial site of C60 solid clusters could be detected by HREM with difference images and RHREM values.