Carbonization of Silicon Nanoparticles via Ablation Induced by Femtosecond Laser Pulses in Hexane

Abstract

Silicon carbide (SiC) has been widely used in various technological applications, including power devices, light-receiving devices, and light-emitting devices. Several methods for fabricating SiC particles with nanometer dimensions have been reported, including carbo-thermal reduction of silica, chemical vapor deposition, laser pyrolysis, and microwave irradiation. To develop a new and simple method for fabricating SiC nanoparticles, we investigated the possibility of using femtosecond-laser ablation. In this paper, we report the formation of SiC nanoparticles by femtosecond-laser ablation on silicon immersed in hexane. By using a high-peak-power laser that can achieve extremely high temperatures and pressures on the silicon surface, SiC nanoparticles were successfully fabricated via ablation in hexane. In our experiments, femtosecond pulses from a Yb-fiber laser were used to irradiate to silicon single crystal. The laser was focused onto a spot on the silicon surface. After ablation, we evaluated the particles on the target substrate and particles in the irradiated hexane. Scanning electron microscopy revealed that the particles range in size from 100 to 400 nm. X-ray diffraction analysis indicated that the nanoparticles might be SiC. The characteristic X-ray photoelectron spectroscopy peaks of nanoparticles were Si-2p (100.1 eV) and C-1s (282.9 eV), which are identical to the characteristic peaks of SiC (John et al. in Handbook of X-ray photoelectron spectroscopy, Physical Electronics, Eden Prairie, 1995; Hijikata et al. in Appl Surf Sci 184:161–166, 2001; Shen et al. in Chem Phys Lett 375:177–184, 2003). We also used transmission electron microscopy and electron energy-loss spectroscopy to evaluate particles from the irradiated hexane. Such a simple method of fabricating SiC nanoparticles by femtosecond-laser ablation may open new possibilities in the development of growth techniques for SiC.