Mechanical properties of diamond films: A comparative study of polycrystalline and smooth fine-grained diamonds by Brillouin light scattering

Abstract

Articles you may be interested inBandgap renormalization in titania modified nanostructured tungsten oxide thin films prepared by pulsed laser deposition technique for solar cell applications J. Appl. Phys.Experimental and theoretical study of bulk light scattering in Ca F 2 monocrystals J. Appl. Phys. 98, 053501 (2005); 10.1063/1.2034085Electron field emission properties of gamma irradiated microcrystalline diamond and nanocrystalline carbon thin films Ex situ spectroscopic ellipsometry investigation of the layered structure of polycrystalline diamond thin films grown by electron cyclotron resonance-assisted chemical vapor deposition Effect of nitrogen addition on the microstructure and mechanical properties of diamond films grown using highmethane concentrations Brillouin light scattering, Raman light scattering and x-ray diffraction were used to investigate the elastic and microstructural properties of polycrystalline and smooth fine-grained diamond films of varying diamond quality. They were deposited on a titanium alloy by a two-step microwave plasma-assisted chemical vapor deposition process at 600°C. Their morphology and roughness were studied by scanning electron microscopy and atomic force microscopy. Their refractive indices were determined by the M-line spectroscopy technique. The diamond purity of all these coatings in terms of the sp 3 bonding fraction was deduced from visible and UV Raman spectroscopy as a function of the deposition conditions. All the samples were found to be textured with a ͗011͘ crystallographic direction normal to the film plane, leading to essentially hexagonal symmetry of the elastic tensor. By taking advantage of the detection of a number of different acoustic modes, complete elastic characterization of the films was achieved. The elastic constants C 11 and C 66 , respectively, were selectively determined from the frequency of the longitudinal and shear horizontal bulk modes traveling parallel to the film surface. The three remaining elastic constants, namely, C 44 , C 33 and C 13 , were obtained from detection of the Rayleigh surface wave a bulk shear wave and the bulk longitudinal wave propagating at different angles from the normal to the surface. The values of the elastic constants depend on the deposition conditions and on the microstructural properties of the films, especially the diamond quality and the polycrystalline or smooth fine-grained nature of the diamond. For the polycrystalline diamond film with the best quality, the elastic constants are rather close to the Voigt or Reuss average estimate values using known bulk elastic constants of diamond, whereas those of the smooth fine-grained diamond films are reduced because of the poorer diamond quality leading to lower residual stress in the films.

Design and investigation of properties of nanocrystalline diamond optical planar waveguides

“…7. Comparison of refractive indices of genuine diamond waveguide, our thin film and the films reported in [7,8,15]. The indices of our thin film (full line) coincide with those of genuine diamond (dash curve)…”

“…6(a)-6(d), the wavelengths of the measurement and, if needed, the thickness of the waveguiding films (380 nm). Figure 7 plots refractive indices of the measured NCD film used in this study and data presented in the previously mentioned works [7,8] are added to compare them with those of the natural diamond [15]. Fig.…”

“…The design of the presented planar waveguides was done on the base of modified dispersion equation and then, an actual NCD film was deposited by microwave plasma enhanced chemical vapor deposition (MW PECVD). This is going to be an approach, different of those already published [7,8], which will lead to deposition of such diamond layers that would be very close to genuine diamond.…”

Elastic Properties of Zinc Blende MnTe

“…For the typical acquisition of a Brillouin spectrum from 2 to 4 hours was required. For a transparent layer a few microns thick, deposited on an opaque substrate, two different geometries of interaction contribute to the inelastic scattering of light from acoustic phonons in the layer [16,17], as shown in the schematic wave vector diagram of Fig. 1.…”

“…The power spectrum of these excitations is mapped out from frequency analysis of the light scattered within a solid angle, by means of a multipass Fabry-Perot interferometer. A number of acoustic modes confined within the film material can thus be revealed, and the elastic constants of the film determined [15][16][17][18].…”