A. Borkowska

Influence of Annealing on Europium Photoexcitation Doped into Nanocrystalline Titania Film Prepared by Magnetron Sputtering

Nanocrystalline TiO 2 films doped by Eu were obtained by low-pressure hot target reactive sputtering at different annealing temperatures and then characterized both structurally and optically. Strong emission assigned to europium ions was observed in the visible range. No emission related to the TiO 2 matrix was detected, indicating an efficient excitation transfer from the matrix to the ions under nonresonant excitation. Europium emission strongly depends on the annealing temperature and reaches a maximum intensity for the sample annealed at 670 K before dropping sharply at higher temperatures. Emission, absorption, and photoluminescence excitation measurements indicate that this effect results from the influence of defect formation at higher temperatures.

Characterization of TiO2 and TiO2-HfO2 Transparent Thin Films for Microelectronics Applications

Transparent oxide semiconductors (TOSs) based on TiO2-doped matrix have been recently studied for their possible microelectronics applications. In the present work, TiO2 and Hf-doped TiO2 thin films were prepared by low pressure hot target reactive magnetron sputtering (LP HTRS) and deposited onto monocrystalline (100) silicon substrate. After deposition thin films were additionally annealed in air for 4 hours at 1000 K. Properties of the thin films matrixes were studied by means of X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). XRD investigations have shown that heat treatment enhances the crystallity of the thin films. Well-shaped lines of the rutile phase for TiO2 and the orthorhombic HfTiO4 have appeared. AFM images showed that the nanocrystalline thin films exhibit the high ordering grade. The dimension and arrangement of grains were homogenous on the whole sample surface. The stoichiometry of manufactured thin films was confirmed by XPS examinations

Studies of electrical and optical properties of thin films of Ti-Pd-Eu oxides prepared by magnetron sputtering

This work presents studies of electrical and optical properties of thin films of oxides based on titanium dioxide prepared by low pressure hot target magnetron sputtering form metallic target. It has been shown that incorporation of Pd and Eu dopants into TiO2 matrix could modify its properties to obtain electrically and optically active oxide-semiconductor with desired type of electrical conduction at room temperature. Thin films of Ti-Pd-Eu oxides were found to be n-type semiconductors. An intense red luminescence (615 nm), corresponding to working range of typical silicon devices, makes the possibility of application such thin films in junction-based photoelectric devices.

Investigations of Electrical Behaviours of Grain Bounadries in Polycrystalline Silicon Solar Cells by EBIC and OBIC

In this work, an application of two non-destructive beam injection methods: Electron Beam Induced Current (EBIC) and Light Beam Induced Current (LBIC) for evaluation of electrical properties of grain boundaries in polycrystalline silicon solar cells have been described. The methods reveal study of the lateral distribution of the current generated by focused electron and light beams and thus the study of local recombination of the charge carriers due to the presence of boundaries.

Photoluminescence and electrical characterization of transparent Eu and Pd-doped TiO2 thin films

In this work, optical and electrical characterization of transparent Eu and Pd-doped TiO2 thin films have been presented. Thin films were deposited by low pressure hot target reactive magnetron sputtering form metallic Ti-Pd-Eu mosaic target on silicon. It has been shown that incorporation of Pd and Eu dopants into TiO2 matrix could modify its properties to obtain electrically and optically active oxide-semiconductor with the electron-type (n) of electrical conduction at room temperature. Pd dopant changes the electrical properties of TiO2 from dielectric oxide to conducting oxide. Eu dopant results in enhanced optical activity of Pd-doped TiO2 thin films in ultraviolet range

Analysis of photoluminescence in TiO 2 matrix doped with Eu and Nd

This work presents the analysis of photoluminescence effect in TiO2 matrix doped with Eu and Nd. Thin films were prepared by high energy reactive magnetron sputtering (HE RMS) method using metallic Ti-Eu and Ti-Nd mosaic targets and deposited on Si and SiO2. After deposition selected films were additionally annealed in an air ambient at 400degC and 600degC. The results of photoluminescence (PL) and optical transmission measurements were analyzed and their correlation with microstructure was described.

Structural properties of transparent Tb-doped TiO 2 thin films

Doping of TiO2 with various metal ions can modify its different properties. In this work, structural properties of transparent Tb-doped TiO2 thin films have been outlined. Thin films were deposited by high energy reactive magnetron sputtering (HE RMS) from metallic Ti-Tb target on Si and SiO2 substrates. Thin films were investigated by means of energy disperse spectrometry (EDS), X-ray diffraction (XRD), atomic force microscopy (AFM) and optical transmission method. From EDS measurements Tb content in prepared thin films was determined to be 0.4 at. %, 2 at. % and 2.6 at. %. XRD analysis revealed the existence of crystalline TiO2 in the form of anatase and rutile, depending on Tb amount in examined samples. AFM images showed nanocrystalline structure of prepared thin films. Optical transmission studies showed that Tb-doped thin films are transparent to visible light. Also, the slight red shift of the fundamental absorption edge of TiO2 was observed with Tb doping.

Transparent thin films based on titanium oxides for photonic applications

The presentation reports on transparent titanium oxide thin film and its photonic applications. Optical transmission and optical beam induced current (OBIC) measurements are presented