Effect of reduction co-sintering on the photoluminescence properties of phosphor in glass in boro-bismuthate glass

Phosphor in glass(PiG) employing Ce:Y_3Al_5O_(12)(YAG)-doped boro-bismuthate glass via low-temperature cosintering technology was successfully prepared, using Bi_2O_3-B_2O_3-ZnO glass as the base material. The photoluminescence(PL) of PiG co-sintered at times ranging from 20 min to 60 min at 700°C was investigated.As a result, the relative PL intensity of PiG under a reducing atmosphere of CO showed significant enhancement of about 7–14 times that under air atmosphere sintering for 20–50 min. The PL intensity decreased gradually with the co-sintering time, which may be due to the corrosion of the YAG lattice structure.     

Effects of surface characteristics on the change of metallic glass structure and magnetoelastic properties induced by laser heat treatment

Laser annealing of amorphous alloy ribbons was performed by irradiating either their smooth or rough side. Experimental results such as hyperfine field distributions, average orientation of the magnetic moment, X-ray diffractography, initial permeability, magnetic anistropy, and low field magnetization, show the influence of the surface characteristics on the effects induced by the laser treatment. In particular, the effects of an applied tensile stress are compared to eachother and with previously obtained results. Many results are explained by means of the crystallization occurrence (at surface and also bulk) and taking into account its dependence on the irradiated surface properties and interaction time.     

Effect of photodarkening on photoluminescence dynamics in CdS-doped glass

We have studied the effect of photodarkening on photoluminescence dynamics in CdS nanocrystals in glass. We have found that the commonly observed increase in the decay rate during photodarkening is spectrally selective, being limited only to the photoluminescence spectral region generally related with carriers in nanocrystal interior states or in shallow traps. On the contrary, the photoluminescence decay rate is exponentially dependent on photon energy (exponential constant of 0.8 eV for the fresh sample) in the spectral interval covering the whole photoluminescence spectrum.     

Effects of selenium treatment on composition and photoluminescence properties of porous silicon

In this work, an ultrasonically enhanced anodic electrochemical etching is developed to fabricate light-emitting porous silicon material. Porous silicon layer is fabricated in n-type (1 0 0) oriented silicon using HF solution and treated in selenious acid to increase the photoluminescence intensity. It is found that the increase of photoluminescence intensity after selenious acid treatment is higher in the intact zones and lower in the detached zones of ultrasonic excitation. The photoluminescence appears as a non-monotonous function of time exposure of selenious acid treatment. Surface chemical composition analysis by X-ray photoelectron spectroscopy shows formation of Si-Se_x and Si-Se_x-O_y on the surface of porous silicon treated with the selenious acid.     

Effect of heat treatment and concentration of Mn and Fe on the structure of borate glass

We have studied the magneto-optic Faraday effect (FE) and electron paramagnetic resonance (EPR) in an aluminum potassium borate glass containing Fe oxides as an impurity in a concentration of 1.5 mass % and Mn impurity in variable concentration from 0 to 1.2 mass %. When manganese oxide is added to the glass composition, the paramagnetic contribution to the Faraday effect increases more slowly than the change in the total concentration of paramagnetic ions, which allows us to hypothesize the appearance of clusters in which the paramagnetic ions are coupled by antiferromagnetic interactions. Formation of clusters upon addition of manganese oxide is confirmed by the change in the nature of the EPR spectra, where we observe a manganese concentration dependence of the distribution of iron atoms with respect to the different positions in the glass matrix. Heat treatment leads to a strong increase in the Faraday effect and a change in the spectral dependences of the Faraday effect and the EPR, which is explained by enlargement of the clusters and appearance of nanoparticles. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 3, pp. 354–358, May–June, 2006.     

Influence of heat treatment on structure and some physical properties of lithium boro-niobate glass

The glass composition (90?mol% Li₂B₄O₇–10?mol% Nb₂O₅) was prepared by the melt quenching technique. The quenched sample was heat treated at 480°C, 545°C and 630°C for 5?h and heat treated at 780°C with different time. The times were 5, 10, 15, 20, 28, and 36?h. The glass and glass ceramics were studied by differential thermal analysis (DTA), X-ray diffraction (XRD), and dc conductivity as a function of temperature. Lithium niobate (LiNbO₃) and lithium diborate (Li₂B₄O₇) were the main phases in glass ceramic addition to traces from LiNb₃O₈. Crystallite size of the main phases determined from the X-ray diffraction peaks are in the range <100?nm. The fraction of crystalline (LiNbO₃) phase increases with increase the heat treatment temperature and time. The relation between physical properties and structure were studied.     

Ge nanoclusters in PECVD-deposited glass after heat treatment and electron-beam irradiation

This paper reports the formation of Ge nanoclusters in silica glass thin films deposited by plasma-enhanced chemical vapor deposition (PECVD). We studied the samples by transmission electron microscopy (TEM) and Raman spectroscopy after annealing. TEM investigation shows that the Ge nanoclusters at two areas were formed by different mechanisms. The Ge nanoclusters formed in a single row along the interface of a silicon substrate and the silica glass film by annealing during high-temperature heat treatment. Ge nanoclusters did not initially form in the bulk of the film but could be subsequently formed by the electron-beam irradiation. The interface between the silicon substrate and the silica glass film was investigated by Raman spectroscopy. The shift of the Raman peaks around 286.8 cm^-1 and 495 cm^-1 suggests that the interface is a Si_1-xGe_x alloy film and that the composition x varies along the film growth direction. PACS 81.07.Bc; 78.66.Jg; 42.65.Wi     

Specific heat of around the glass transition

Dynamic calorimetric measurements are performed for the quaternary metallic glass Zr₆₅Al_7.5Cu_17.5Ni₁₀ in order to analyse the dependence on different heating rates for the glass transition temperature T_g. We compare two different temperature programs used for sample relaxation, to estimate the influence of the thermal history on T_g. A lower limit for the glass transition temperature T_g was calculated according to two different models based on the fact, that width and temperature of the glass transition depend on the experimental time scale set by the heating rate: One model assumes a Vogel-Fulcher-Tammann type behaviour, as used to describe more or less “fragile” glass formers and the other assumes an Arrhenius-like behaviour, which is related to “strong” glass formers. The values obtained from both models differ by about 80K. From additional absolute specific heat capacity measurements we calculate the Kauzmann temperature T_K, as a lower limit for the temperature of the glass transition from thermodynamic aspects. Comparing T_K with the temperature values obtained from the two evaluation models we can classify the quaternary metallic glass Zr₆₅Al_7.5Cu_17.5Ni₁₀, to behave more like a “strong” glass former. Received: 23 January 1998 / Received in final form and Accepted: 31 August 1998     

铝对过渡金属离子掺杂的二氧化硅溶胶凝胶玻璃发光性质的影响

用溶胶凝胶法制备了过渡金属离子(Ni2+,Mn2+和Cu2+)单掺、铝共掺的二氧化硅玻璃,测量了荧光光谱、吸收光谱和红外光谱,研究了Al3+对过镀金属离子在二氧化硅玻璃中发光性质的影响。研究结果表明,Al3+对过渡金属离子的发光性质有着显著影响:Ni2+,Mn2+和Cu+的发光强度大幅度提高,Mn2+的发光峰峰位改变。     

The effect of alkaline earth metallic ions on the photoluminescence properties of sol-gel silica glass

Mg²⁺-, Ca²⁺-, Sr²⁺- and Ba²⁺-doped silica glasses have been prepared using sol-gel processing by employing Si(OC₂H₅)₄, MgCl₂6H₂O, CaCl₂2H₂O, SrCl₂6H₂O and BaCl₂2H₂O as precursors, with HCl as a catalyst. The UV–visibleabsorption spectra of the doped samples are almost the same as those of the undoped sample. The absorption bands of alkaline earth metallic ions have not been observed in the doped samples. Strong visible light has been observed from sol- gel silica glasses doped with alkaline earth metallic ions. The relative fluorescence intensity of the Sr²⁺-doped (the impurity mole ratio of Sr²⁺ was 0.268%) and the Ba²⁺-doped (the impurity mole ratio of Ba²⁺ was 0.448%) samples was about 4 times that of the undoped sample. The relative fluorescence intensity of the Mg²⁺-doped (the impurity mole ratio of Mg²⁺ was 0.069%) sample was about 2.5 times that of the pure glass sample. The relative fluorescence intensity of the Ca²⁺- doped (the impurity mole ratio of Ca²⁺ was 0.179%) sample was about 3 times that of the pure glass sample. Alkaline earth metallic ions affect the formation and conversion of luminescent defects in sol-gel silica glass. Thus, the relative fluorescence intensity of the doped samples increases more than that of the undoped sample. Received: 17 April 2001 / Accepted: 6 June 2001 / Published online: 30 August 2001     

Dependence of photoluminescence of n-GaAs on surface treatment

The changes in the intensity, shape and location of characteristic photoluminescence lines caused by various surface treatments in Te doped GaAs samples at 80 K were studied. The depth of the damage caused by such treatment is estimated. An explanation of the shifts of the characteristic lines based on the varying contribution of far donor-acceptor pairs is proposed.     

The effects of heat treatment on microfluidic devices fabricated in silica glass by femtosecond lasers

We fabricated complex microfluidic devices in silica glass by water-assisted femtosecond laser ablation and subsequent heat treatment.The experimental results show that after heat treatment,the diameter of the microchannels is significantly reduced and the internal surface roughness is improved.The diameters of the fabricated microchannels can be modulated by changing the annealing temperature and the annealing time.During annealing,the temperature affects the diameter and shape of the protrusions in microfluidic devices very strongly,and these changes are mainly caused by uniform expansion and the action of surface tension.     

超声处理对ZnO薄膜光致发光特性的影响

对于结晶状态好的ZnO薄膜，测量了其光致发光(PL)光谱，发射光谱中只发现了峰值波长约389 nm的近紫外光.样品进行超声处理后，发射谱中不仅观察到近紫外峰，又观察到波长约508 nm的绿光峰.绿光峰的强度比近紫外光的强度强得多，且近紫外峰红移.进一步的热处理使绿光峰大大增强.超声处理改变了ZnO薄膜的质量和结晶状态，使晶格中产生氧空位.处理过程中的热效应使得薄膜晶格振动加剧.当晶格振动加剧到一定程度，晶格中的氧脱离格点形成氧空位.510 nm左右的绿色发光峰是ZnO晶体中的氧空位产生的.薄膜的温度越高， 关键词： ZnO薄膜 超声 光致发光     

The influence of heat treatment on the ultrasonic velocity and elastic moduli of a Zr-Cu-Ni-Al-Ti bulk metallic glass

The influence of heat treatment at temperatures up to 550°C on the elastic properties of the Zr_52.5Cu_17.9Ni_14.6Al₁₀Ti₅ bulk amorphous alloy is investigated using acoustical measurements. The results obtained are compared with calorimetric and x-ray diffraction data.     

退火对多晶ZnO薄膜结构与发光特性的影响

用射频反应溅射法在Si（111）衬底上制备了C轴取向的多晶ZnO薄膜，通过不同温度的退火处理，研究了退火对多晶ZnO薄膜结构和发光特性的影响.由x射线衍射得知，随退火温度的升高，晶粒逐渐变大，薄膜中压应力由大变小至出现张应力.光致发光测量发现，样品在430nm附近有一光致发光峰, 峰的强度随退火温度升高而减弱，联合样品电阻率随退火温度升高而逐渐变大的测量及能级图，推测出ZnO薄膜中的蓝光发射主要来源于锌填隙原子缺陷能级与价带顶能级间的跃迁. 关键词： ZnO薄膜 退火 光致发光 射频反应溅射     

Effects of thermal oxidation on the photoluminescence properties of porous silicon

The effects of thermal oxidation on the photoluminescence (PL) properties of powdered porous silicon (PSi) are studied using X-ray photoelectron spectroscopy (XPS). It is found that the PL intensity is steeply quenched after annealing at and recovered at above . The XPS intensity of oxides formed on the PSi surface is also found to strongly depend on the annealing temperature. The comparison between the annealing temperature dependence of PL intensity and that of the oxide XPS intensity suggests that the formation of thin disordered SiO₂ layer accompanies the quenching of the PL intensity, and that the formation of thick high-quality SiO₂ layer results in the PL intensity recovery. These results indicate that the thickness and quality of SiO₂ layer play a crucial role in the PL properties of thermally oxidized PSi.     

有机吸附物对多孔硅微腔发光的影响

理论上,采用Bruggeman有效介质近似,研究了有机吸附物对多孔硅微腔的折射率及其光致发光谱的影响.实验上,采用计算机控制的电化学腐蚀法制备了多孔硅微腔样品,并利用机械泵油的蒸气分子与该微腔样品进行相互作用.研究发现,多孔硅微腔发射的窄化光致发光谱对泵油蒸气分子的吸附与脱附很敏感,与之伴随的是该窄化光致发光谱发生明显的峰位移动(可达71nm)和强度变化.结合Bruggeman近似和表面态对多孔硅发光的影响,对实验结果进行了定性解释.实验结果与理论模拟结果符合较好. 关键词： Bruggeman近似 吸附物 多孔硅微腔 光致发光谱     

Effect of deformation and heat treatment on the damping constant and shear modulus of a bulk Zr-Cu-Ni-Al-Ti metallic glass

The effect of deformation by rolling or quenching from temperatures close to the glass transition temperature on the damping constant and the shear modulus of preliminarily annealed bulk samples of a Zr_52.5Ti₅Cu_17.9Ni_14.6Al₁₀ metallic glass was studied. These treatments are found to result in recovery of the “irreversible” contributions to the damping constant and the shear modulus, and the deformation treatment is shown to lead to an increase in the amplitude-dependent internal friction.     

两片掺铒玻璃样品级联荧光光谱的实验研究

介绍一种掺铒玻璃样品的制作方法，实验测量了单片及两片掺铒玻璃样品的荧光特性.结果表明：两片掺铒玻璃样品级联的荧光强度比单片掺铒玻璃样品的荧光强度高，半值宽度与高浓度单片样品的半值宽度近似相等；在两片掺铒玻璃样品级联的形式中，浓度高的样品靠近抽运光源时的荧光强度比浓度低的样品靠近抽运光源时的荧光强度高；两种低浓度样品组合的荧光强度相对于其单片样品荧光强度的增幅比两种高浓度样品组合的荧光强度相对于其单片样品荧光强度的增幅要高. 关键词： 掺铒玻璃样品 级联 荧光光谱强度 半值宽度