With electron assisted chemical vapour deposition technology, some nanocrystalline diamond films have been deposited, which precipitate polycyclic aromatic clusters in the film matrix. Optical properties of the films have been characterized. The results of characteristics show that Raman and photoluminescence spectrum of the films conform to identity of pyrene except for diamond peaks; photoluminescence emission spectrum of the films show stronger emission peaks at 385nm and 470nm. Our results show that purer polycyclic aromatic clusters of four fused sixfold ring, which are the same as pyrene in structure, can form in the nanocrystalline diamond film matrix by bombarding the films with electrons.
