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141.
J.H RangelN.L.V Carreño E.R Leite E LongoC.E.M Campos F Lanciotti Jr.P.S Pizani J.A Varela 《Journal of luminescence》2002,99(2):85-90
Pb1−XLaXTiO3 thin films, (X=0.0; 13 and 0.27 mol%) were prepared by the polymeric precursor method. Thin films were deposited on Pt/Ti/SiO2/Si (1 1 1), Si (1 0 0) and glass substrates by spin coating, and annealed in the 200-300°C range in an O2 atmosphere. X-ray diffraction, scanning electron microscopy and atomic force microscopy were used for the microstructural characterization of the thin films. Photoluminescence (PL) at room temperature has been observed in thin films of (PbLa)TiO3. The films deposited on Pt/Ti/SiO2/Si substrates present PL intensity greater than those deposited on glass and silicon substrates. The intensity of PL in these thin films was found to be dependent on the thermal treatment and lanthanum molar concentration. 相似文献
142.
K. Song H.K. Cha V.A. Kapitanov Yu.N. Ponomarev A.P. Rostov D. Courtois B. Parvitte V. Zeninari 《Applied physics. B, Lasers and optics》2002,75(2-3):215-227
The results of theoretical and experimental studies and the design of a multi-purpose differential Helmholtz resonant photoacoustic
detector (DHRD) and its applications to high-resolution spectroscopy of molecular gases and gas analysis with a room-temperature
diode laser in the near-IR region are summarized. The series of experiments and numerical analysis of the DHRD sensitivity
were performed for both types (single-pass and multi-pass) of DHRDs within a wide pressure range 0.1–101 kPa, including the
regime of a gas flowing through a DHRD cell. The hardware and electronic arrangement of DHRDs for diode laser spectrometers
and gas analyzers providing a limiting absorption sensitivity better than 10-7 Wm-1 are described. The results of measurements of spectral line parameters of H2O near 800 and 1390 nm and CH4 near 1650 nm (intensities, line broadening and shifting by atomic and molecular gases) are presented and discussed. The problems
and the ways of perfection of the methodology and accuracy of DHRD techniques with tunable diode lasers of near-IR and visible
spectral ranges are discussed.
Received: 1 April 2002 / Revised version: 20 June 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +7/382-225-8026, E-mail: kvan@asd.iao.ru 相似文献
143.
Amorphous SiOx thin films with four different oxygen contents (x=1.15, 1.4, 1.5, and 1.7) have been prepared by thermal evaporation of SiO in vacuum and then annealed at 770 or 970 K in argon for various times ?40 min. The influence of annealing conditions and the initial film composition on photoluminescence (PL) from the annealed films has been explored. Intense room temperature PL has been observed from films with x?1.5, visible with a naked eye. It has been shown that PL spectra of most samples consists of two main bands: (i) a ‘green’ band centered at about 2.3 eV, whose position does not change with annealing conditions and (ii) an ‘orange-red’ band whose maximum moves from 2.1 to 1.7 eV with increasing annealing time and temperature and decreasing initial oxygen content. These observations have been explained assuming recombination via defect states in the SiOx matrix for the first band and emission from amorphous Si nanoparticles for the second one. 相似文献
144.
The photo-physical properties of Xanthene dyes: Basic Rhodamine Yellow (BRY), Rhodamine590perchlorate (R590p), SulforhodamineB (SRB) doped in tetramethylorthosilicate (TMOS) and poly-methylmethacrylate (PMMA) are observed. The various parameters viz. full-width at half-maxima (FWHM), peak emission wavelength, quantum yield and excited state lifetime at different concentrations ranging from ∼0.05 to ∼1 mM of the dye under excitation by Copper Vapor Laser (CVL) of high repetition rate (∼5.6 kHz) of are investigated. In order to identify photostability in dyes, normalized photostability has been studied and found that silica gel samples containing dye are more stable than that of polymeric samples. This has been further understood in terms of number density of unbleached dye molecules that infers that photobleaching of dye molecules is not prominent at higher concentrations in glassy solid matrices. Pump intensity dependent optical gain of the samples has also been reported and efforts have been made to study the efficiency of solid-state laser samples in a cavity for the performance of the dye laser. 相似文献