CuO,CuCl对P2O5-ZnO-Na2O玻璃性质的影响

包边技术是提高大尺寸激光玻璃饱和增益系数的关键。为获得优质包边玻璃,以CuO和CuCl分别作为Cu2+的引入物质,采用传统的玻璃熔制方法,研究了Cu2+掺杂量和不同引入物质对P2O5-ZnO-Na2O体系玻璃形成区、析晶稳定性、物化性能以及吸收系数的影响。研究结果表明,CuO和CuCl都能增大P2O5-ZnO-Na2O体系的玻璃形成区、提高玻璃样品的析晶稳定性。玻璃样品的吸收系数随Cu2+掺杂浓度的增加而明显增大,当Cu2+掺杂摩尔分数达到6%时,样品在1053 nm处的吸收系数为59.46 cm-1,基

飞秒激光辐照ZnO晶体

利用飞秒激光对ZnO晶体进行辐照，对辐照前后的晶体样品进行发光光谱及拉曼光谱检测。辐照后发光光谱的某些发光峰强度有明显增强，但未产生新的发光峰，表明没有新的缺陷结构产生，但晶体内锌空位、间隙位锌、间隙位缺陷浓度增加。拉曼光谱结果表明，辐照后ZnO晶体未产生相变，但随着辐照激光功率的增大，拉曼峰327 cm-1，437 cm-1强度明显减弱，表明在飞秒激光辐照作用下氧化锌的结晶程度下降。但574 cm-1峰值却随着辐照功率的增大而变大，分析表明该拉曼峰很可能是由于晶体内间隙位缺陷所致。同时实验过程中观察到飞

Frequency up-conversion properties of Er3(+)-doped TeO2-ZnO-PbCl2 oxyhalide tellurite glasses

This paper reports on the successful preparation and a detailed study on the up-conversion properties of Er3+ -doped TeO2-ZnO-PbCl2 oxylialide tellurite glasses. Three intense emissions centered at around 527, 549 and 666 nm have been clearly observed under 977 nm excitation and the involved mechanisms have been explained. The green emissions centered at 527 and 549 nin are due to the H-2(11/2 ->) I-4(15/2) and S-4(3/2) -> I-4(15/2) transitions, and the red up-conversion emission centered at 666 nm is associated with the F-4(9/2) -> I-4(15/2) transitions of Er3+ ions, respectively. The quadratic dependence of fluorescence on excitation laser power confirm that two-photons contribute to up-conversion of the green-red emissions. (c) 2005 Elsevier B.V. All rights reserved.

Thermal analyses, spectral characterization and structural interpretation of Yb3+ doped TeO2-ZnO-ZnCl2 glasses

Bulk-lasses have been prepared in the TeO2-ZnO-ZnCl2 systems. Their characteristic temperatures were determined and analyzed. Raman and FT-IR spectra were used to analyze the effect of ZnCl2 on the structure and spectral properties of tellurite glasses and OH- groups in this glass system. The spectroscopic properties including absorption spectra, emission cross-sections and fluorescence lifetimes of Yb3+ in TeO2-ZnO-ZnCl2 were measured and calculated. It is demonstrated that the progressive replacement less than 20 mol% of TeO2 by ZnCl2 improves the thermal stability, removes the OH- groups, turns TeO4 bipyramidal arrangement into TeO3 (and/or TeO3+1) trigonal pyramids structures and results in the decrease of the symmetry of the structure, which increases the emission cross-sections and lifetimes. But when the content of ZnCl2 up to 30 mol%, the glass system becomes more hygroscopic and introduces more OH- groups, which decrease the emission cross-sections and shorten the lifetimes. The results show that the glass system with (TeO2)-Te-69-(ZnO)-Zn-10-20ZnCl(2)-1Yb(2)O(3) is a desirable component for active laser media for high power generation. (c) 2005 Elsevier B.V. All rights reserved.

Preparation and characterization of hybrid ZnO/ormosils films

Hybrid ZnO/ormosils Elms are prepared by the sol-gel method. A FT-IR spectrometer, 900 UV/VIS/NIR spectrophotometer, atomic force microscope, and ellipsometer are employed to investigate microstructure and optical properties of the films fired at different temperatures. The results show that the films with high transmittance and low surface roughness could be obtained at the heat-treatment temperature of 150 degrees C, the refractive index and thickness of the film are 1.413, 2.11 mu m, respectively. Higher temperatures (350 degrees C, 550 degrees C) change the Elm microstructure severely, and then decrease the transmittance of the films.

Photoluminescence of undoped and B-doped ZnO in silicate glasses

Photoluminescence of undoped and B-doped ZnO in silicate glasses was investigated by varying the concentration of ZnO (3550 mol%) and B dopant (0-10 mol%) in the glass matrices. The broad and intense near band edge emissions were observed while the visible light emission was very weak. UV luminescence in all samples was red-shifted relative to the exciton transition in bulk ZnO and enhanced by decreased ZnO concentration due to higher degree of structural integrity and the lower aggregation degree of ZnO. Donor B dopant played the double roles of filling conduction bands to broaden band gap when its concentration was lower than 5 mol%, and emerging with conduction bands to narrow the gap when B dopant exceeded this value. (c) 2007 Elsevier B.V. All rights reserved.

Effects of sapphire substrate annealing on ZnO epitaxial films grown by MOCVD

The annealing effects of sapphire substrate on the quality of epitaxial ZnO films grown by metalorganic chemical vapor deposition (MOCVD) were studied. The atomic steps formed on (0 0 0 1) sapphire (alpha-Al2O3) substrate surface by annealing at high temperature was analyzed by atomic force microscopy (AFM). The annealing effects of sapphire substrate on the ZnO films were examined by X-ray diffraction (XRD), AFM and photoluminescence (PL) measurements. Experimental results indicate that the film quality is strongly affected by annealing treatment of the sapphire substrate surface., The optimum annealing temperature of sapphire substrates is given. (c) 2006 Elsevier B.V. All rights reserved.

Epitaxial growth of ZnO films on (100) and (001) gamma-LiAlO2 substrates by pulsed laser deposition

Structural and optical properties were investigated for ZnO films grown on (100) and (001) gamma-LiAlO2 (LAO) substrates by pulsed laser deposition method. According XRD results, it is intuitionistic that (100) LAO is suitable for fabricating high quality ZnO film, while (001) LAO is unsuitable. The FWHM of XRD, stress in film and FWHM of UV PL spectra for ZnO films on (100) LAO show a decreasing with increasing substrate temperature from 300 to 600 degrees C. ZnO film fabricated at 600 degrees C has the greatest grain size, the smallest stress (0.47 Gpa) and PL FWHM value (similar to 85 meV). This means that the substrate temperature of 600 degrees C is optimum for ZnO film deposited on (100) LAO. Moreover, it was found that the UV PL spectra intensity of ZnO film is not only related to the grain size and stoichiometric, but also depends on the stress in the film.

Epitaxial growth of ZnO thin films on LiGaO2 substrates by pulsed-laser deposition

Lattice-matched (Delta(a/a) = 1.8-3.4%) (001) LiGaO2 substrates have been employed for the first time to grow ZnO thin films by pulsed-laser deposition at 350-650 degrees C with oxygen partial pressure of 20Pa. XRD shows that a highly c-axis-oriented ZnO film can be deposited on (001) LiGaO2 substrate at 500 degrees C. AFM images reveal the surfaces of as-deposited ZnO films are smooth and root-mean-square values are 6.662, 5.765 and 6.834 nm at 350, 500 and 650 degrees C, respectively. PL spectra indicate only near-band-edge UV emission appears in the curve of ZnO film deposited at 500 degrees C. The deep-level emission of ZnO film deposited at 650 degrees C probably results from Li diffusion into the film. All the results illustrate substrate temperature plays a pretty important role in obtaining ZnO film with a high quality on LiGaO2 substrate by pulsed-laser deposition. (c) 2006 Elsevier B.V. All rights reserved.

Broadband infrared luminescence from Li2O-Al2O3-ZnO-SiO2 glasses doped with Bi2O3

The broadband emission in the 1.2 similar to 1.6 mu m region from Li2O-Al2O3-ZnO-SiO2 ( LAZS) glass codoped with 0.01mol.% Cr2O3 and 1.0mol.% Bi2O3 when pumped by the 808nm laser at room temperature is not initiated from Cr4+ ions, but from bismuth, which is remarkably different from the results reported by Batchelor et al. The broad similar to 1300nm emission from Bi2O3-containing LAZS glasses possesses a FWHM ( Full Width at Half Maximum) more than 250nm and a fluorescent lifetime longer than 500 mu s when excited by the 808nm laser. These glasses might have the potential applications in the broadly tunable lasers and the broadband fiber amplifiers. (c) 2005 Optical Society of America.

MOCVD growth and properties of ZnO thin films on LiNbO3 substrates

ZnO thin films were grown on (0001)LiNbO3 substrates by the MOCVD technique. The substrate temperatures during growth were changed from 400 to 600 degrees C. The X-ray diffraction (XRD) pattern of the ZnO film showed a strong [002] reflection peak, and the peak intensity was dependent on substrate temperature. The ZnO columnar grains were highly oriented along the (002) direction when the film processing temperature was 600 degrees C. The optical transmission and PL results also indicated that highest crystalline quality of the ZnO films could be obtained at elevated temperatures. (c) 2005 Elsevier B.V. All rights reserved.

Annealing effect on properties of ZnO thin films grown on LiNbO3 substrates by MOCVD

ZnO films were grown on (0 0 0 1) LiNbO3 substrates by metal organic chemical vapor deposition (MOCVD). Annealing of ZnO films was performed in air for I h at 800 degrees C. The effects of annealing on the structural and optical properties of ZnO thin films on LiNbO3 substrates were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM) and photoluminescence (PL) measurements. XRD patterns and AFM showed that the as-grown and the annealed ZnO films grown on LiNbO3 substrates had c-axis preferential orientation, the crystallinity of the ZnO films grown on LiNbO3 Substrates was improved, and the grain size increased by annealing. The PL spectra showed that the intensity of the UV near-band-edge peak was increased after annealing, while the intensity of visible peak (deep-level emission) decreased. (c) 2005 Elsevier B.V. All rights reserved.

Growth and properties of ZnO thin film on beta-Ga2O3(100) substrate by pulsed laser deposition

Zinc oxide (ZnO) thin films were grown on the beta-Ga2O3 (100) substrate by pulsed laser deposition (PLD). X-ray diffraction (XRD) indicated that the ZnO films are c-axis oriented. The optical and electrical properties of the films were investigated. The room temperature Photoluminescence (PL) spectrum showed a near band emission at 3.28 eV with two deep level emissions. Optical absorption indicated a visible exciton absorption at room temperature. The as-grown films had good electrical properties with the resistivities as low as 0.02 Omega cm at room temperature. Thus, beta-Ga2O3 (100) substrate is shown to be a suitable substrate for fabricating ZnO film. (c) 2006 Elsevier B.V. All rights reserved.

Optical properties of ZnO thin film on gamma-LiAlO2 substrate grown by pulsed laser deposition

Optical properties were investigated of ZnO thin films grown oil (100) gamma-LiAlO2 (LAO) substrates by pulsed laser deposition method. C-axis oriented ZnO film was grown oil (100) LAO substrate at the substrate temperature of 550 degrees C. The transmittances of the films were over 85%. Peaks attributed to excitons were seen in the absorption spectra, indicating that the thin films have high crystallinity. Photoluminescence spectra were observed at room temperature; the peak at 550 urn is ascribed to oxygen vacancies in the ZnO films caused by the diffusion of Li from the substrate into the film during deposition. (c) 2005 Elsevier B.V. All rights reserved.