Thin films of indium molybdenum oxide (IMO) were rf sputtered onto glass substrates at room temperature. The films were studied as a function of sputtering power (ranging 40-180 W) and sputtering time (ranging 2.5-20 min). Thickness of the films found varied between 50-400 nm. The films were characterized for their structural (XRD), electrical (Hall measurements) and optical (Transmittance spectra) properties. XRD studies revealed that the films are amorphous for the sputtering power ≤ 100 W and deposition time ≤ 5 min. All the other films are polycrystalline and the strongest refection along (222) plane showing a preferential orientation. A minimum bulk resistivity of 2.65 × 10-3 Ω-cm and a maximum carrier concentration of 4.16 × 1020 cm-3 have been obtained for the films sputtered at 180 W (10 min). Whereas maximum mobility (19.5 cm2 V-1 s-1) has been obtained for the films sputtered at 80 W (10 min). A maximum visible transmittance of 90% (500 nm) has been obtained for the films sputtered at 80 W (10 min) with a minimum of 27% for those sputtered at 180 W. The optical band gap of the films found varying between 3.75 and 3.90 eV for various sputtering parameters. © 2006 Materials Research Society.

This work focuses on the role of the native oxide layer (SiO2) on the nickel (Ni)-assisted crystallization of amorphous silicon (a-Si). In some samples, the native oxide was removed using a HF-diluted solution before Ni layers with 0.5 nm be deposited on a-Si. The results show that the presence of a thin SiO2 layer of about 3 nm between the a-Si and the Ni delays the crystallization process. Ellipsometry data show that, after annealing for 5 h at 500 °C, the HF-cleaned sample presents a crystalline fraction of 88%, while the one with the native oxide has only 35%. This difference disappears after 20 h where both samples present similar crystalline fraction. These facts are also reflected on the film's electrical properties, where the activation energy for samples annealed for 5 h rises from 0.42 eV to 0.55 eV, when the oxide layer is removed. After 20 h and 30 h, the activation energy is around 0.55 eV for both kinds of samples, meaning that films with similar electrical properties are now obtained. However, the XRD data suggest the presence of some structural differences attributed to slight differences on the crystallization process. © 2005 Elsevier B.V. All rights reserved.

Total hip replacement is a common practice in every day clinical work. Artificial hip implants consist of a femoral component and an acetabular component. Nowadays the acetabular component is composed of a polymeric cup and a metallic shell. This study focuses the development of an innovative acetabular component substituting the metallic shell by a multilayer coating on the acetabular cup. A titanium coating was deposited onto ultra-high molecular weight polyethylene (UHMWPE) samples by physical vapour deposition (PVD), having an in situ pre-treatment with argon ion bombardment in order to optimize the adhesive strength by surface modification, followed by the deposition of a thin film of hydroxyapatite (HA) using rf magnetron sputtering technique, at room temperature. Results obtained seem to indicate that these multilayer coatings can be a viable alternative to the metallic shell, leading to the substitution of a two part for a one part acetabular component.

Cobalt oxide thin films were prepared by using the dipping sol-gel process. The films were deposited onto glass slides, starting from methanolic solution of cobalt acetate Co(CH3COO)2 · 4H2O. The effects of film thickness and sol concentration on structural and optical properties were studied. Structural analyses of Co3O4 films were performed by X-ray diffraction. The film thickness was varied by using different withdrawal speeds and the number of dipping-heating cycles. It was found that the grain size increases with the number of dipping N. The results point out to some compacting effect that increases with the number of dippings: the films exhibit direct and indirect optical transition, absorption coefficients are of the order of 104 cm-1, and upon annealing the absorption coefficient increases. © 2006 Elsevier B.V. All rights reserved.