Target-plane deposition of diamond-like carbon in pulsed laser ablation of graphite

• Published in: Applied surface science Vol. 253; no. 24; pp. 9521 - 9524
• Main Authors: Yap, S.S., Tou, T.Y.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.10.2007; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Diamond-like carbon; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Impact phenomena (including electron spectra and sputtering); Infrared and Raman spectra; Infrared and raman spectra and scattering; Laser ablation; Laser-beam impact phenomena; Nanostructure; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Physics; Raman spectra; Raman spectra; Nanostructure; Diamond-like carbon; Laser ablation; Melting; Phase transformations; Physical radiation effects; Nanostructures; Pulsed lasers; Film growth; Surface structure; Laser radiation; Graphite; Laser ablation technique; Surface layers; Formation mechanism
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2007.06.032

In pulsed Nd:YAG laser ablation of highly oriented pyrolytic graphite (HOPG) at 10 −6 Torr, diamond-like carbon (DLC) are deposited at laser wavelengths of 1064, 532, and 355 nm on substrates placed in the target-plane. These target-plane samples are found to contain varying sp 3 content and composed of nanostructures of 40–200 nm in size depending on the laser wavelength and laser fluence. The material and origin of sp 3 in the target-plane samples is closely correlated to that in the laser-modified HOPG surface layer, and hardly from the backward deposition of ablated carbon plume. The surface morphology of the target-plane samples shows the columnar growth and with a tendency for agglomeration between nanograins, in particular for long laser wavelength at 1064 nm. It is also proposed that DLC formation mechanism at the laser-ablated HOPG is possibly via the laser-induced subsurface melting and resolidification.