Discrimination of Different Amorphous Carbon by Low Fuence Laser Irradiation

Carbon thin film deposition was carried out with nanosecond or femtosecond laser ablation from two different sp2-bonded carbon targets, in particular highly oriented pyrolytic graphite (HOPG) and glassy carbon (GC). Raman measurements indicated that theses as-deposited films are amorphous carbon and could be similar in terms of the D and G Raman bands ratio. Moreover, these films are not easily distinguishable from each other by transmission electron microscopy observation due to their amorphous structure. In this work, we show that laser irradiation of thin film below the ablation threshold fuence is an interesting approach which permits the structural difference between them to be revealed and provides some structural information on as-deposited thin film