INVESTIGATION OF METALLIC NANOPARTICLES PRODUCED BY LASER ABLATION METHOD AND THEIR CATALYTIC ACTIVITY ON CVD DIAMOND GROWTH

The synthesis of high quality diamond films is one of the particular interests due to the material's outstanding physical and mechanical properties. In CVD diamond we found a new process parameter window where the growth of diamond films can be stabilized without the use of diamond powder on substrates. Using suitable catalyst and etching gas would enhance the diamond nucleation and therefore, increase the quality of the films. A laser ablation was conducted by using an optical system for producing the metallic nanoparticles. A light source with a first harmonic generator (FHG) of an Nd:YAG laser were used with the wavelength of 1064 nm, pulse duration: 6 ns and repetition rate of 10 Hz. Au and Ag nanoparticles were dried on the Si and glass wafers as a catalyst and etching treated by hydrogen plasma for 30 minutes. Topography of the wafers was analyzed using Atomic Force Microscopy (AFM) and shows a good distribution of the nanoparticles on the substrate surface. Diamond films were deposited on substrates coated metal using a Hot Filament Chemical Vapor Deposition (HFCVD) system. Crystallinity of the samples was observed by X-ray diffraction (XRD) method. Results show good quality diamond crystals with crystallinity of (311) structures, grown on substrate surface. According to the Scherrer formula, the grain size (L-hkl) of diamond nano crystals were calculated by L-hkl=K lambda/B cos theta(hkl), where B is the FWHM in radians and lambda is the wavelength in nm.