Raman Spectroscopy of Amorphous Carbon Films Modified by Single‐Pulse Irradiation of Nanosecond and Femtosecond Lasers

Abstract

Structural modifications of tetrahedral amorphous carbon (ta-C) films, caused by single-pulse laser irradiation, were investigated. Graphitization of the films, content and size of sp 2 carbon clusters were analyzed by means of Raman spectroscopy. It has been shown that pulse duration, as well as laser fluence and wavelength of irradiation, strongly influence the processes of graphitization and ablation of the ta-C films. In particular, heating of the films by the laser beam leads to formation of sp 2 carbon clusters and their enlargement up to the size of several nanometers. Material transformation to graphitized fraction is much more efficient in case of ns pulse duration. In case of fs pulse duration, such factors as multiphoton absorption and evaporation of over-heated material from the surface at high laser fluence, shorter time of irradiation, and heat transfer to the inner layers of the film lead to relatively weak graphitization characterized by the maximum size of the sp 2 carbon clusters of about 1 nm.

Revisiting thin film of glassy carbon

“…Amorphous carbon (a-C) is widely reported in the literature and used in many applications due to the large adaptability of its properties [1][2][3][4][5][6][7][8][9][10]. Its structure contains short range ordered domains mixing three hybridizations sp, sp 2 and sp 3 with different proportions of each them depending on deposition experimental parameters which in turn determines their properties.…”

Tailoring of Silver Nanoparticle Size Distributions in Hydrogenated Amorphous Diamond‐Like Carbon Nanocomposite Thin Films by Direct Femtosecond Laser Interference Patterning

“…The Raman scattering spectrum ( Figure 1b) of the DLC-0 sample is consistent with similar spectra reported in other studies describing amorphous hydrogenated DLC films (a-C:H). [18,19,33,34] The peak at 1535 cm À1 in the DLC-0 Raman scattering spectrum and the shoulder at around 1400 cm À1 are commonly attributed to G peak (bond stretching vibration of all pairs of sp 2 carbon atoms) and D peak (shoulder at lower wavenumbers related to the breathing vibration modes of sp 2 bonded rings). Usually, ratio of these two peaks is used to characterize the ratio of sp 3 to sp 2 bonds in DLC.…”

“…[15] Applying close to Gaussian distribution tightly focused laser beams, it is possible to reach close to half-wavelength resolution using direct laser interference patterning (DLIP), which is a highly reproducible and easily scalable micromachining method. [11] Although laser ablation mechanisms of various DLC films were quite extensively investigated, [11,[16][17][18][19] studies on laser ablation and laser-induced effects of metal containing DLC films are still very limited. [9] Depending on the energy densities applied, carbonaceous films are usually ablated, delaminated, or graphitized, [11] whereas the nanoparticles can melt, coalesce, or fragment.…”

“…Although laser ablation mechanisms of various DLC films were quite extensively investigated, studies on laser ablation and laser‐induced effects of metal containing DLC films are still very limited . Depending on the energy densities applied, carbonaceous films are usually ablated, delaminated, or graphitized, whereas the nanoparticles can melt, coalesce, or fragment .…”

Nanocarbon Photonics and Optoelectronics

“…The productive discussions during the meeting (which has been held on 19–24 March 2017) were provided by perfect organization and nice natural environment, including ski slopes, at Krasnaya Polyana resort (Sochi, Russia). The contributions (in total an amount of 30) of this Special Issue are covering research work related to production, characterization and application of the nanocarbon materials which include diamonds, carbon nanotubes, graphene other types of nanocarbon materials, and their composites . Traditionally for the NPO Workshop series there is also some portion of reports devoted to non‐carbon materials demonstrating properties and phenomena analogous to those observed for nanocarbons.…”