Fast Growth of Diamond Crystals in Open Air by Combustion Synthesis with Resonant Laser Energy Coupling

Abstract

Fast growth of diamond crystals in open air was achieved by combustion synthesis with resonant laser energy coupling. A premixed C 2 H 4 /C 2 H 2 /O 2 gas mixture was used as precursors for growth of diamond crystals. Through the resonant excitation of the CH 2 wagging mode of the ethylene (C 2 H 4 ) molecules using a CO 2 laser tuned at 10.532 μm, high-quality diamond crystals were grown on silicon substrates with a high growth rate at ∼139 μm/h. Diamond crystals with a length up to 5 mm and a diameter of 1 mm were grown in 36 h. Sharp Raman peaks at 1332 cm -1 with full width at half-maximum (fwhm) values around 4.5 cm -1 and distinct X-ray diffraction spectra demonstrated the high quality of the diamond crystals. The effects of the resonant laser energy coupling were investigated using optical emission spectroscopy.

Seed-Free Growth of Diamond Patterns on Femtosecond Laser Processed Silicon Substrates

“…This is because for the synthesis method, the contact area between deposited diamond and substrate is insufficient for heat diffusion when the Si surface has extremely high roughness. As reported in previous studies, high-quality diamond is obtained within a narrow window of 760-780 °C, and a high temperature above the window promotes graphitic carbon deposition [13,23]. Comparing the deposited diamond in figure 5, it is found that a dense diamond film would not be formed even after long time deposition at the roughness of R a 0.24814 and 0.17601 µm, while that of R a 1.08849 and 0.47646 µm can provide sufficient nucleation sites for thin film formation.…”

“…In our experiment, we employed the laser-assisted combustion synthesis method for diamond deposition mentioned in our previous work [13][14][15]. The flow rates of O 2 , C 2 H 2 and C 2 H 4 were fixed at 1200, 620, and 620 sccm by mass flow controllers, respectively.…”

“…The temperature of deposition site was maintained to be 760-780 °C through adjusting the water flow rate. A CO 2 laser 10.532 µm at wavelength and 800 W at power energy was used to resonantly excite the CH 2 wagging mode (ν 7 , 949.3 cm -1 ) of the C 2 H 4 precursor molecules [13].…”

Carbon nanogears and nanotori via combustion flames

“…Diverse carbon nanomaterials, such as diamond/diamond-like ones [1][2][3], graphite polyhedral crystals [4][5][6], carbon nano thin films [7], carbon nanotubes [8] and graphene [9,10], have been widely investigated based on CF methods due to their extraordinary mechanical, optical and electrical properties. The diamond grains from micrometer [1,2] to millimeter scale [3] have been reported, which showed the potential applications of the CF for super hard materials. The graphite polyhedral crystals exhibited unusual sevenfold, ninefold [4], octahedron [5] and more complex axial symmetry [6].…”

Resonant effects in nonlinear photon absorption during femtosecond laser ablation of Nd-doped silicate glass

“…In order to achieve resonant absorption, the laser wavelength is tuned to achieve one of the resonant transitions to an excited state in an atom or a molecule. In comparison to ordinary laser ablation, RLA can be used to improve ablation efficiency and promote ablation selectivity, which has been demonstrated to play an important role in physics, chemistry, and other industrial applications [5,6].…”