Discrimination of different amorphous carbon by low fluence laser irradiation

Abstract

Carbon thin film depositions were carried out with femtosecond laser ablation from two different sp2-bonded carbon targets, namely highly oriented pyrolytic graphite (HOPG) and glassy carbon (GC). Femtosecond laser deposition is generally known as a means of generating nanoparticles. To our knowledge, Raman spectroscopy is not able to directly discriminate the as-deposited amorphous films which may contain different sp2 carbon nanoclusters while still showing similar Raman spectra. 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 controlled laser irradiation of thin films at low fluence is an interesting approach to reveal the existence of structural differences for amorphous films deposited from sp2 carbon targets (HOPG and GC).

Keywords

• Glassy carbon
• Pyrolytic graphite
• Pulsed laser deposition
• Low fluence laser irradiation
• Raman spectroscopy