Bonding character of the boron-doped C60 films prepared by radio frequency plasma assisted vapor deposition

Boron-doped C60 thin films were synthesized firstly by a radio frequency plasma assisted vapor deposition technique using C60 as a precursor. The surface morphology of the samples was observed by atomic force microscopy, and their chemical bonding characters were investigated by x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The results show that the boron atoms are incorporated into the fullerene molecules in the samples, and the boron heterofullerene C60−nBn was synthesized. Plasma polymerized C60 molecules were also found in the samples besides the boron heterofullerene. The effects of radio frequency power and the substrate position on the growth of the B-doped C60 films were studied. The results indicate that the higher energies and densities of the reactive radicals in the plasma are favorable for the formation of the boron heterofullerene C60−nBn or polymerized C60 molecules.