Product Code: ICA10_P154

Laser-Induced Resonant Vibrational Excitations of Precursor Molecules in Multi-Energy Processing for Diamond Synthesis
Authors:
Z.Q. Xie, Department of Electrical Engineering, University of Nebraska-Lincoln; Lincoln NE USA
X.N. He, Department of Electrical Engineering, University of Nebraska-Lincoln; Lincoln NE USA
Y. Gao, Department of Electrical Engineering, University of Nebraska-Lincoln; Lincoln NE USA
Y.S. Zhou, Department of Electrical Engineering, University of Nebraska-Lincoln; Lincoln NE USA
J.B. Park, Department of Electrical Engineering, University of Nebraska-Lincoln; Lincoln NE USA
T. Guillemet, Department of Electrical Engineering, University of Nebraska-Lincoln; Lincoln NE USA
Y.F. Lu, Department of Electrical Engineering, University of Nebraska-Lincoln; Lincoln NE USA
Presented at ICALEO 2010

Multi-energy processing (MEP) using lasers is very appealing in materials synthesis. By directly coupling energy to desired vibrational and electronic states of reacting molecules, reactions can be controlled with high efficiency and high yield. How to couple laser energies into reactions is of extreme importance in the MEP. Here we report laser resonant excitations of precursor molecules in combustion flame synthesis of diamond. A wavelength-tunable CO2 laser (spectrum range from 9.2 to 10.9 μm) was used for the resonant excitations. A pre-mixed CB2BHB4B/CB2BHB2B/OB2B gas was used as precursors for the growth of diamond. Laser energy is coupled into the reactions through resonant excitations of the CHB2B wagging mode of ethylene (CB2BHB4B) molecules by tuning the wavelength to 10.532 µm. Diamond growth rate as well as diamond quality were promoted by laser resonant excitations. High-quality diamond crystals were grown on silicon substrates with a high growth rate of ~139 µm/h. Diamond crystals up to 5 mm in height and 1 mm in diameter were grown in 36 hours. Sharp Raman peaks at 1332 cmP-1P with full width at half maximum (FWHM) values around 4.5 cmP-1P and distinct X-ray diffraction spectra indicate the high quality of the diamond crystals.