Some Biological and Physical Properties of Laser Deposited Hydroxyapatite Based Films

The preliminary results of biological and physical tests of hydroxyapatite thin films deposited on dental implants by a new technology with the KrF excimer laser ablation method were evaluated. Biological and physical properties were studied and analyzed by the lymphocyte proliferation test and scanning electron microscopy (SEM), X-ray analysis, Rutherford backscattering analysis (RBS) and particle induced X-ray emission (PIXE) methods. Ten bioceramic films from 45 samples had very good physical and biological properties. Creation of hydroxyapatite thin films with laser ablation can have a positive effect on adhesion of the film and protection for corrosion

Nanostructures Defined by The Local Oxidation of Ferromagnetic GaMnAs Layer

The results of Local Anodic Oxidation (LAO) on the thin GaMnAs layers are reported. The ferromagnetic GaMnAs layers were prepared by low temperature MBE growth in a Veeco Mod Gen II machine. The LAO process was performed with the AFM microscope Smena NT-MDT placed in the sealed box with the controlled humidity in the range 45-80%. The oxide was grown in the semi-contact mode of the AFM. Sample was positively biased with respect to the AFM tip with the bias from 6 to 24 V. The conductive diamond coated AFM tips with the radius 30 nm were utilized for the oxidation. The tip speed during the oxidation was changed from 400 nm/s to 1.5 μm/s. The tip force was also changed during the oxidation. The height of oxide nanolines increases with applied voltage from 3 to 18 nm. The width of these lines was approximately 100 nm at half of the maximum

Preliminary Study of Ge-DLC Nanocomposite Biomaterials Prepared by Laser Codeposition

This paper deals with the synthesis and study of the properties of germanium-doped diamond-like carbon (DLC) films. For deposition of doped DLC films, hybrid laser technology was used. Using two deposition lasers, it was possible to arrange the dopant concentrations by varying the laser repetition rate. Doped films of Ge concentrations from 0 at.% to 12 at.% were prepared on Si (100) and fused silica (FS) substrates at room temperature. Film properties, such as growth rate, roughness, scanning electron microscopy (SEM) morphology, wavelength dependent X-ray spectroscopy (WDS) composition, VIS-near infrared (IR) transmittance, and biological properties (cytotoxicity, effects on cellular morphology, and ability to produce reactive oxygen species (ROS)) were studied in relation to codeposition conditions and dopant concentrations. The analysis showed that Ge-DLC films exhibit cytotoxicity for higher Ge doping

On the Origin of Reduced Cytotoxicity of Germanium-Doped Diamond-Like Carbon: Role of Top Surface Composition and Bonding

This work attempts to understand the behaviour of Ge-induced cytotoxicity of germanium-doped hydrogen-free diamond-like carbon (DLC) films recently thoroughly studied and published by Jelinek et al. At a low doping level, the films showed no cytotoxicity, while at a higher doping level, the films were found to exhibit medium to high cytotoxicity. We demonstrate, using surface-sensitive methods—two-angle X-ray-induced core-level photoelectron spectroscopy (ARXPS) and Low Energy Ion Scattering (LEIS) spectroscopy, that at a low doping level, the layers are capped by a carbon film which impedes the contact of Ge species with tissue. For higher Ge content in the DLC films, oxidized Ge species are located at the top surface of the layers, provoking cytotoxicity. The present results indicate no threshold for Ge concentration in cell culture substrate to avoid a severe toxic reaction

Nitrogen rich carbon nitride thin films deposited by hybrid PLD technique

Highly nitrogenated CNx, films were created by pulsed laser deposition (PLD), combined with radiofrequency (RF) and hollow cathode (HC) discharges. The N/C ratio higher than 1 was measured. Deposition set- up and results of optical measurement are discussed.SCOPUS: cp.jProceedings of the 6th International Conference on Frontiers of Polymers and Advanced Materials: A Conference on Advanced Materials, Emerging New Technologies and Business Opportunities; Recife; Brazil; 4 March 2001 through 9 March 2001.info:eu-repo/semantics/publishe

Chemical-bond effect on epitaxial strain in perovskite sodium niobate

Epitaxial films and heterostructures of perovskite oxides attract tremendous scientific interest because of the unique phenomena therein. Especially important is the epitaxial growth of films subjected to substrate-induced misfit strain. We show here that in contrast to conventional misfit-controlled epitaxy, chemical bonds determine the crystal stability and strain in epitaxial films of sodium niobate on different cubic substrates. Strain relaxation in sodium niobate is independent of misfit magnitude and proceeds through perovskite-specific tilting of oxygen octahedra in addition to common defect formation. The observed structural relaxation evidences a major role of a large internal strain that originates from chemical bonds in the perovskite cell. The effect of chemical bonds on film strain is anticipated to also control the epitaxy of other perovskite oxides and related compounds.Peer reviewe

Comparative characterization of nitrogen-rich CNx films prepared by different ICP-CVD techniques

Thin amorphous nitrogen-rich CNx films (N/(C+N) ≥ 0.5) have been prepared by two inductively coupled plasma chemical vapour deposition (ICP-CVD) techniques: using transport reactions from a solid carbon source and from CCl4/NH3/Ar and CCl4/N2/H2/Ar gas mixtures. Optical emission spectroscopy (OES) and quadrupole mass spectrometry were used to derive information about the plasma properties. The composition of the films was investigated by Anger electron spectroscopy (AES), wavelength dispersive X-ray (WDX) and elastic recoil detection (ERD) analyses, and the chemical bonding structure by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. In addition, several application relevant properties (mechanical, optical, electrical) of the nitrogen-rich CNx films were studied. The results of both deposition methods were compared and discussed on the base of the specificities of the processes.13th European Conference on Chemical Vapor Deposition (EUROCVD 13); Athens; Greece; 26 August 2001 through 31 August 2001.info:eu-repo/semantics/publishe