Product Code: ICA11_N205

Laser-Power-Resolved Excitations of Ethylene Molecules in Laser-Assisted Synthesis of Diamond Films
Authors:
Z.Q. Xie, University of Nebraska-Lincoln; Lincoln NE
X.N. He, University of Nebraska-Lincoln; Lincoln NE
W. Hu, University of Nebraska-Lincoln; Lincoln NE
Y. Gao, University of Nebraska-Lincoln; Lincoln NE
T. Guillemet, University of Nebraska-Lincoln; Lincoln NE
J.B. Park, University of Nebraska-Lincoln; Lincoln NE
Y.S. Zhou, University of Nebraska-Lincoln; Lincoln NE
Y.F. Lu, University of Nebraska - Lincoln; Lincoln NE USA
Presented at ICALEO 2011

Laser-power-resolved excitations of precursor molecules in laser-assisted synthesis of diamond films using a wavelength-tunable CO2 laser were studied. The wavelength of the CO2 laser was tuned to 10.532 µm to match a vibration mode of a precursor molecule, ethylene (C2H4). The density of the incident laser power was adjusted to modify diamond crystal orientation, optimize diamond quality, and achieve high-efficiency laser energy coupling. It was observed that at incident laser power densities between 5x10^3 and 1.0x10^4 W/cm2, (100)-faceted diamond crystals were grown uniformly in the center areas of the diamond films. Higher incident laser powers, although further promoted growth rate, suppressed the uniformity of the diamond (100) facets. Best diamond quality was obtained within a laser power density range of 5x10^3 ~ 6.7x10^3 W/cm2, whereas the highest energy efficiency was achieved within a laser power density range of 3.3x10^3 ~ 6.7x10^3 W/cm2. The effects of the resonant laser energy coupling were investigated using optical emission spectroscopy and mass spectrometry.