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In the present work, optical, structural and morphological properties of CdS-doped phosphate films obtained by pulsed laser deposition (PLD) method were investigated. In the deposition process, a target based on a mixture composed of LiO-AlO-BaO-LaO-ZnO-PO glass and CdS powder as dopant was used. The phosphate glass target was obtained by non-conventional wet route of raw reagents processing followed by melt-quenching technique. The complex oxide composition of the glass as well as the final PLD target consisting in a mixture of glass and CdS powder followed by pressing and heat treatment represents the novelty of the work. CdS dopant particles were highlighted by X-ray diffraction analysis as well as by Raman spectroscopy. Thus, cubic CdS particles having less than 10 nm size corroborated with specific LO (longitudinal optical phonons) and 2LO CdS Raman peaks from 300 and 600 cm, respectively, certified the presence of the dopant in the deposited films. Specific vibration modes for the vitreous phosphate matrix were revealed by fourier transform infrared spectroscopy, and spherulitic units characteristic to PLD technique were found by scanning electron microscopy and atomic force microscopy analyses. A relative large luminescence band located around 430 nm was provided by UV excitation, representative for CdS nanoparticles having about 9-10 nm size. [ABSTRACT FROM AUTHOR]

Doped organic compounds are of great interest for optical communications and high-density optical data storage due to their large second-order nonlinearity and high-speed response. A promising approach in the fabrication of new materials for second-order nonlinear optics is sol-gel technique. The present paper reports on the sol-gel synthesis of some pyrazolone derivative doped SiO-PO films. The precursors used for sol gel synthesis were tetraethylorthosilicate and phosphoric acid (HPO). The organic compound was added under continuous stirring in the precursors' mixture. The structure of the deposited azo-derivatives doped thin films was examined by Fourier transform infrared spectroscopy, and atomic force microscopy and their optical properties by UV-VIS spectroscopy. The nonlinear optical efficiencies due to the interaction of the NLO-active chromophores with the inorganic matrix has a significant influence on the second harmonic generation capabilities that was measured using a femtosecond Ti:sapphire laser. The properties of the films were investigated and correlated with the concentration of the organic dopant and the thermal treatment temperature. [ABSTRACT FROM AUTHOR]

Silicate and silicophosphate films doped with CdSe/ZnS quantum dots (QDs) have been deposited on silicon substrate, by sol-gel method, spin-coating technique. A precursor solution (PS) composed of tetraethoxysilane (TEOS) and ethanol (EtOH) has been prepared in the case of silicate films (T) and in the case of silicophosphate films (TPT), the same precursors for T films and triethylphosphate were used. In each PS, dimethylformamide and CdSe/ZnS (QD) were added. Spectroscopic ellipsometry shows that absorption of TPT films in the visible (400-700 nm) decreases over 400 nm, due to dimensional quantum effect of semiconductor doping particles embedded in the silicophosphate matrix. The same manner is noticed in the case of refractive index dependency on wavelength. Raman spectra were recorded by 785 nm excitation and put in evidence specific bands for the inorganic matrix as well as a low-intensity band characteristic for CdSe doping. The morphology of the films was investigated by transmission electron microscopy revealing semiconductor doping dots with average dimension 3.3 nm and a homogeneous distribution of the doping particles in the inorganic matrix. SEM image of the cross-section of the TPT film reveals a thickness of about 500 nm. The fluorescence spectra of CdSe/ZnS-doped films exhibit an emission band at about 530 nm, provided by 350 nm excitation, whose characteristics are close to those of CdSe compound. [ABSTRACT FROM AUTHOR]

SiO-PO films doped with CdSe have been prepared and investigated for temperature sensors applications. The films have been synthesized by sol-gel method, spin coating technique, the deposition being made on glass substrates. The sols have been prepared from tetraethylorthosilicate (TEOS) and phosphoric acid as precursors for SiO and PO, respectively, together with ethanol and water as reaction environment and a hydrolysis reagent, respectively. The films have been deposited at three rotation rates: 1000, 2000 and 3000 rpm, starting on the first day after the sol preparation moment and going on, four days consecutively, and then on the eighth day. We have analyzed the influence of the rotation rate and the time elapsed since the sol preparation till the deposition moment on the structural properties of the doped films. The films deposited at each rotation rate have been annealed at 200, 300, 350, 400, and 550°C in order to investigate the structural modifications noticed during the formation process of silicophosphate network. [ABSTRACT FROM AUTHOR]

We intend to prepare periodic multilayered structures for photonic applications. With this goal we have performed a study of some characteristics of SiO x -P2O5 films deposited by the sol–gel method on glass and ITO (InSnO x )-coated glass. The as prepared films were annealed to different temperatures (150 and 200°C). The chemical composition of the samples was determined by X-ray Photoelectron Spectroscopy (XPS). The XPS results revealed the presence of P in the as-deposited films. The structural an optical properties were examined by Fourier Transform Infrared Spectroscopy (FTIR), Spectroellipsometry (SE) and UV Transmission Spectroscopy. IR spectra of the deposited films attest the interaction of an amorphous SiO2 with the H3PO4 used as a P-precursor. Refractive indices for individual SiO x -P2O5 determined from SE measurements show a densification of the layer structure with the increasing temperature in the thermal treatment. The UV transmission spectra revealed a lower transmission for the sol-gel SiO x -P2O5 films as compared to ITO/glass substrate. AFM images proved the densification of the films with annealing in agreement with the ellipsometric results. [ABSTRACT FROM AUTHOR]