Product Code: ICA11_N206

Synthesis of Nitrogen-Doped Diamond Films by Vibrational Excitation of Precursor Molecules Using CO2 Laser in a Combustion Flame Process
Authors:
Lisha Fan, University of Nebraska-Lincoln; Lincoln NE
Zhiqiang Xie, University of Nebraska-Lincoln; Lincoln NE
Jongbok Park, University of Nebraska-Lincoln; Lincoln NE
Xiangnan He, University of Nebraska-Lincoln; Lincoln NE
Yunshen Zhou, University of Nebraska-Lincoln; Lincoln NE
Y.F. Lu, University of Nebraska - Lincoln; Lincoln NE USA
Presented at ICALEO 2011

Nitrogen-doped diamond films were synthesized by resonantly exciting ammonia (NH3) molecules in an ammonia-added-oxy-acetylene flame. A wavelength-tunable CO2 laser (spectrum range from 9.2 to 10.9 μm) was used for the resonant excitations. The NH wagging mode of the NH3 molecules was selected to achieve the resonant excitations. Both laser wavelengths of 10.591 and 9.219 m were applied to the process to compare the NH3 excitations and diamond deposition. Compared with 10.591 um produced by common CO2 lasers, the laser wavelength of 9.219 um is much more effective in resonant excitation of the NH3 molecules through the NH wagging mode. With a 500 W laser excitation at 9.219 um, a high quality nitrogen-doped diamond film was deposited with a doping level of 1.51020 N atoms/cm3. A morphologic inversion from an amorphous cauliflower structure to a columnar diamond structure was observed before and after the resonant laser excitation. Potential growth mechanisms were investigated and discussed.