Oxidation-Based Continuous Laser Writing in Vertical Nano-Crystalline Graphite Thin Films

Loic Loisel (1) , Ileana Florea (2) , Costel-Sorin Cojocaru (2) , Beng Kang Tay (1) , Bérengère Lebental (3)

1 Nanyang Technological University [Singapour]
2 LPICM - Laboratoire de physique des interfaces et des couches minces [Palaiseau]
3 IFSTTAR/COSYS/LISIS - Laboratoire Instrumentation, Simulation et Informatique Scientifique

Nano and femtosecond laser writing are becoming very popular techniques for patterning carbon-based materials, as they are single-step processes enabling the drawing of complex shapes without photoresist. However, pulsed laser writing requires costly laser sources and is known to cause damages to the surrounding material. By comparison, continuous-wave lasers are cheap, stable and provide energy at a more moderate rate. Here, we show that a continuous-wave laser may be used to pattern vertical nano-crystalline graphite thin films with very few macroscale defects. Moreover, a spatially resolved study of the impact of the annealing to the crystalline structure and to the oxygen ingress in the film is provided: amorphization, matter removal and high oxygen content at the center of the beam; sp2 clustering and low oxygen content at its periphery. These data strongly suggest that amorphization and matter removal are controlled by carbon oxidation. The simultaneous occurrence of oxidation and amorphization results in a unique evolution of the Raman spectra as a function of annealing time, with a decrease of the I(D)/I(G) values but an upshift of the G peak frequency.

Mots clés: CONTINUOUS LASER; RAMAN SPECTROSCOPY; TEXTURED CARBON

Mots clés: OXYDATION

Domaines: Micro et nanotechnologies/Microélectronique

Loic Loisel, Ileana Florea, Costel-Sorin Cojocaru, Beng Kang Tay, Bérengère Lebental. Oxidation-Based Continuous Laser Writing in Vertical Nano-Crystalline Graphite Thin Films. Scientific Reports, 2016, 9p. ⟨10.1038/srep26224⟩. ⟨hal-01393408⟩