Search

The studies were conducted to assess the structural evolution and nucleation of Si-nanocrystal in silicon-rich silicon oxide films produced by PECVD (plasma enhanced chemical vapor deposition), as a function of the annealing temperature. The findings reveal the active role played by the hydrogen and nitrogen atoms in the formation of Si-nc and in the thermally induced evolution of the deposited films.

Research describing nucleation and crystallization in oxide glasses is presented. In particular the size distribution and structure of nanoparticles in the glass matrix is investigated.

Light-emitting porous Si that luminesce at room temperature exhibit a degradation of the electroluminescence with time and strong laser heating effects. Light emitting porous Si can be obtained by the anodic etching of p-type Si samples in a HF-ethanol solution, and its properties can be studied using an Auger or Raman spectroscopy. Photoluminescence is more efficient than electroluminescence.

Micro-Raman spectroscopy and x-ray diffraction techniques were used to compare and characterize rhenium oxide thin films obtained by thermal evaporation of Re[O.sub.3] powders on different substrates, maintained at different temperatures and by reactive magnetron sputtering of a Re metallic target. The electrical and electro-optical behaviors of Re[O.sub.3] films deposited on standard indium tin oxide/glass substrate tested inside asymmetric nematic liquid crystal cells showed an ability to rectify their electro-optical response similar to tungsten trioxide.

A systematic study of the microstructural evolution of Si-rich SiO(sub x) films, after ion irradiation and postirradiation heat treatment is carried out by means of vibrational spectroscopy techniques. Si-rich silicon oxide films are proposed on c-Si (100) wafers by a rf (13.56 MHz) plasma-enhanced chemical vapor deposition apparatus from SiH4 and N2O gas mixtures under different flow ratios N2O/SiH4.

The spin-dependent tunneling between a magnetite (111) sample and an antiferromagentic tip though a vacuum barrier is examined with the help of spin-polarized (SP) scanning tunneling magnetization (STM). An oxygen top layer changes the SP properties of the magnetite surface considerably.

Plasma-enhanced chemical vapor deposition resulted in silicon-rich silicon oxide films. The ion bombardment was promoting the formation of amorphous Si nanoclusters along with reduction of open volume in the matrix and substantial release of hydrogen.

Fabricated tips from antiferromagnetic MnNi were used to discuss the surface properties of magnetite, Fe3O4(001). It is concluded that STM images of Fe3O4 are obtained by probing the Fe cation states, which form the corrugation along the atomic rows on the surface.

Pure ground WO3 and (1-x)WO(sub 3-y).xReO2 mixtures using x-ray absorption spectroscopy, x-ray powder diffraction and Raman spectroscopy are studied and compared with hydrogen bronzes HxWO3 and hydrogenated CaWO4:H. Results show that grinding pure WO3 decreases crystallites size and leads to the formation of a bluish coloration. The (1-x)WO(sub 3-y).xReO2 mixtures were also made up of monoclinic/orthorcombic WO3 and orthorhombic ReO2 phases.