Er3+掺杂Ge-Ga-S-KBr硫卤玻璃的中红外发光和多声子弛豫的研究

用熔融急冷法制备了系列不同Er3+离子掺杂浓度的Ge-Ga-S-KBr硫卤玻璃,测试了样品折射率、吸收光谱、中红外荧光光谱。通过吸收光谱计算了Er3+离子吸收谱线的振子强度,应用Judd-Ofelt理论计算分析了Er3+离子在Ge-Ga-S-KBr硫卤玻璃中的强度参数Ωi ( i = 2 , 4 , 6) 、自发辐射跃迁几率A、荧光分支比?和辐射寿命?rad等光谱参数。研究了808nm激光泵浦下样品中红外荧光特性与掺杂浓度之间变化关系,并用Futchbauer-Ladenburg公式分别计算了2.8?m处的受激发射截面。结果表明,在808nm 激光泵浦下观察到了2.8?m中红外荧光,分别对应于Er3+： 4I11/2?4I13/2跃迁,当Er3+离子掺杂浓度从0.4wt%增加到1.0wt%时,中红外荧光强度都随相应增加,计算的Er3+:4I11/2?4I13/2跃迁多声子驰豫速率分别为37 s-1。     

荧光俘获效应对Er3+/Yb3+共掺杂碲钨酸盐玻璃光谱性质的影响

制备了掺杂浓度相同而厚度不同的Er^3 ／Yb^3 共掺杂碲钨酸盐玻璃样品,测量了样品的吸收光谱和970nmLD激发下的Er^3 离子1．5um发射的荧光光谱和荧光寿命,计算了Er^3 离子的发射截面,研究了荧光俘获效应对Er^3 离子1．5um发射的光谱性能的影响。结果表明,样品中Er^3 离子存在很强的荧光俘获效应,且荧光俘获效应随样品厚度的增加而增强。荧光俘获效应使测得的荧光寿命比计算的自发辐射寿命要长,随样品厚度的增加,Er^3 离子1．5um发射的荧光寿命增加;其荧光有效线宽△λeff与次峰值强度和主峰值强度的比值,Ⅰa/Ⅰp也增加,且△λeff与Ⅰa／Ⅰp存在很好的线性关系。首次提出采用Er^3 1．5um波段荧光谱的次峰值强度和主峰值强度的比值,Ⅰa／Ⅰp与从McCumber理论计算得到的次峰值发射截面和主峰值发射截面的比值(σea／σep)的差值或比值来判断基质中Er^3 1．5um波段荧光俘获效应强弱的方法。     

Er3+掺杂铌磷酸盐玻璃材料的光谱性质

采用熔融猝灭方法制备了掺杂不同浓度Er^3 离子的铌磷酸盐玻璃材料，测量了该材料的吸收光谱、发射光谱和荧光寿命。计算了在该玻璃材料中Er^3 的光学跃迁强度参数，同时计算了部分能级之间光学跃迁的振子强度、跃迁几率以及辐射跃迁寿命。应用两种不同的方法计算了^4I13／2→^4I15／2受激发射截面，结果证明存在的自吸收很小。荧光寿命随浓度的变化关系表明，^4I13／2能级的能量传递是电偶极类型的，同时证明在低浓度下该能级的量子效率接近100％。所有这些研究结果表明，该材料可能成为新的集成光学器件材料的候选者。     

Er3+单掺和Er3+/Yb3+双掺铋硼酸盐玻璃的研究

用高温熔融法制备了Er^3 单掺和Er^3 /Yb^3 双掺铋硼酸盐玻璃样品，测量了上述玻璃样品的吸收光谱，荧光光谱，荧光寿命以及红外透过率。对高浓度掺杂Er^3 的铋硼酸盐玻璃中的浓度猝灭现象作出了解释。分析了Er^3 ／Yb^3 双掺铋硼酸盐玻璃样品中Yb^3 离子对Er^3 离子的敏化过程。研究发现Er^3 ／Yb^3 双掺铋硼酸盐玻璃在1．5～1．6μm波段有宽达81nm的荧光半峰全宽。实验还发现在熔制过程中通入氧气对其荧光寿命和红外透过率都有明显的提高。由于该玻璃材料表现出较好的物化性能。因此该材料可望成为宽带光纤放大器的适宜的基质材料。     

Er：YLF晶体中Er^3＋离子的光谱特征

利用居地－奥非脱（Ｊｕｄｄ－Ｏｆｅｌｔ）理论计算了Ｅｒ＾３＋离了在氟化钇锂（ＬｉＹＦ４简写为ＹＬＦ）晶体中的辐射跃迁几率Ａｊｊ无辐射跃迁几率ωＪＪ及激发态荧光寿命τ，并根据荧光动力学方程计算出各激发态布居数ＮＪ与掺杂浓度ｘ的关系，对２．７μｍ激光（＾４Ｉ１１／２→＾４Ｉ１３／２）来说，掺杂浓度要大于～３ａｔ％，才能实现布居数反转，对波长为１．７３μｍ的＾４Ｉ１３／２→＾４Ｉ１５／２跃迁，存在荧光强     

掺杂Er3+多组份氧化物玻璃的制备与发光特征的研究

用高温熔融法制备了用于1．5μm光波段元件高浓度Er^3 掺杂的B2O3－SiO2,Al2O3-SiO2-CdO与Li2O-Al2O3-SiO2三种多组分氧化物玻璃。在488nm连续氩离子激发下,测定并比较了这三种玻璃在1．5μm波段的发射光谱特征,及掺杂浓度对发光强度的影响。研究结果表明：Er^3 :Li2O-Al2O3-SiO2具有较宽的发光带,是合适的光放大器玻璃基质材料;而B2O3－SiO2玻璃系统随Er^3 掺杂浓度的增加,其荧光效应成线性增强,是合适的发光基质。     

TeO2-ZnO-Na2O-K2O玻璃中Er3+离子掺杂浓度对其发光及荧光寿命的影响

测量了不同掺杂浓度下Er3+离子在碲酸盐玻璃中的吸收光谱、发射光谱和Er3+离子的荧光寿命,计算了Er3+离子的发射截面σe,分析了Er3+离子掺杂浓度对其发光强度和荧光寿命的影响.结果表明,Er3+离子掺杂浓度较低时,对其荧光强度和荧光寿命没有显著的影响;掺杂浓度高时,出现了浓度猝灭效应,使Er3+离子荧光光强度降低,荧光寿命下降.实验确定了掺杂浓度最优值,同时对浓度猝灭机制进行了分析.     

荧光俘获效应对掺饵氧化物玻璃光谱性质的影响

测试了不同掺杂浓度和样品厚度下掺铒磷酸盐和碲酸盐玻璃的吸收光谱、荧光光谱和荧光寿 命，计算了Er³⁺离子在1.53 μm处的吸收截面(σ_a)、发射截面(σ _e)、自发辐射跃迁概率(A_rad)、辐射跃迁寿命(τ_rad) 、以及辐射跃迁量子效率(η)等光谱参数.讨论了荧光俘获效应对掺铒磷酸盐和碲酸盐玻璃 光谱性质及光谱参数的影响.结果表明即使在铒离子低掺杂浓度(0.1 mol% Er₂O ₃)下，荧光俘获效应也普遍存在于掺铒玻璃材料中，使得荧光寿命(τ_{f)和荧光半高宽(FWHM)随样品的厚度和铒离子掺杂浓度增加而增大，导致碲酸盐和磷酸 盐玻璃中τf分别增加11%—37％和6%—17%，FWHM分别增加15%—64%和11%—55% ，使得掺铒玻璃材料的放大品性参数(σe×FWHM) 也相应被估高.由于铒离子在 碲酸盐玻璃中在1.53 μm处吸收和发射截面重叠面积较大，加之铒离子在前者基质中的发射 截面高于后者，使得掺铒碲酸盐玻璃中的荧光俘获效应高于磷酸盐玻璃. 关键词： 荧光俘获 铒离子 碲酸盐玻璃 磷酸盐玻璃}     

Er~(3+)掺杂Ge-Ga-S-KBr硫卤玻璃的中红外发光和多声子弛豫的研究

为了获得能输出中红外荧光的理想基质玻璃,用熔融急冷法制备了系列不同Er3+离子掺杂浓度的Ge-Ga-S-KBr硫卤玻璃,测试了样品折射率、吸收光谱、中红外荧光光谱.通过吸收光谱计算了Er3+离子吸收谱线的振子强度,应用Judd-Ofelt理论计算分析了Er3+离子在Ge-Ga-S-KBr硫卤玻璃中的强度参量Ωi(i=2,4,6)、自发辐射跃迁几率A、荧光分支比β等光谱参量.研究了808nm激光抽运下样品中红外荧光特性与掺杂浓度之间变化关系,并用Futchbauer-Ladenburg公式分别计算了2.8μm处的受激发射截面.结果表明,在808nm激光抽运下观察到了2.8μm中红外荧光,对应于Er3+:4I11/2→4I13/2跃迁,当Er3+离子掺杂浓度从0.4wt%增加到1.0wt%时,中红外荧光强度相应增加,计算的Er3+:4I11/2能级的多声子驰豫速率为37s-1.     

Er3+单掺及Yb3+/Er3+双掺LaLiP4O12玻璃光谱性质研究

制备了Er3 +单掺杂及Yb3+/Er3+双掺杂四磷酸盐玻璃 ,测量了吸收光谱、荧光光谱 ,用McCumber理论计算Er3 +的发射截面 ,研究了其荧光特性、浓度猝灭及其机制、以及OH基对荧光强度和能量传递的影响 ,研究发现对四磷酸盐玻璃Yb3+的最佳浓度约为 1.82× 10 2 1ions/cm3,Er3+最佳浓度约为 0 .96× 10 2 0 ions/cm3。     

掺铒SiOx的光致发光特性

利用分子束外延设备生长了掺铒SiO_x,观察到铒掺入的同时O的掺入效率也得到提高.铒可以促进氧的掺入的原因是铒与氧在硅衬底表面反应，以络合物形式掺入硅中，从而提高了硅中氧的浓度.测量了铒在SiO_x中的光致发光特性，结果表明掺铒的SiO_x的发光强度从18K到300K仅下降了约1/2，这说明Er掺在SiO_x中是一种降低发光强度的温度淬灭效应的途径，最后讨论了温度淬灭的机制. 关键词：     

Enhanced emission of Er from alternately Er doped Si-rich Al2O3 multilayer film with Si nanocrystals as broadband sensitizers

Alternately Er doped Si-rich Al₂O₃ (Er:SRA) multilayer film, consisting of alternate Er-Si-codoped Al₂O₃ (Er:Si:Al₂O₃) and Si-doped Al₂O₃ (Si:Al₂O₃) sublayers, has been synthesized by co-sputtering from separated Er, Si, and Al₂O₃ targets. The dependence of Er³⁺ related photoluminescence (PL) properties on annealing temperatures over 700-1100 °C was studied. The maximum intensity of Er³⁺ PL, about 10 times higher than that of the monolayer film, was obtained from the multilayer film annealed at 950 °C. The enhancement of Er³⁺ PL intensity is attributed to the energy transfer from the silicon nanocrystals in the Si:Al₂O₃ sublayers to the neighboring Er³⁺ ions in the Er:Si:Al₂O₃ sublayers. The PL intensity exhibits a nonmonotonic temperature dependence: with increasing temperature, the integrated intensity almost remains constant from 14 to 50 K, then reaches maximum at 225 K, and slightly increases again at higher temperatures. Meanwhile, the PL integrated intensity at room temperature is about 30% higher than that at 14 K.     

镱铒共掺Al2O3薄膜光致发光特性优化

用中频磁控溅射方法在SiO2/Si基底上制备了五组固定掺铒浓度不同镱铒浓度比率的镱铒共掺Al2O3薄膜样品.室温下测量了薄膜在1.430 μm~1.630 μm波段范围内光致发光光谱.研究发现,镱的掺入有效地提高了三价铒离子的光致发光强度,最优的镱铒掺杂为：掺铒0.33 mol%,Yb3+∶Er3+=10∶1,比相同掺铒浓度单掺铒样品光致发光峰值强度增强40倍;确定的掺铒浓度,有着固定的最佳镱铒浓度比率,主要是镱铒离子间的正向和反向能量传递相互作用的结果,但最佳镱铒浓度比率随着掺铒浓度的增加呈现下降趋势;单掺铒薄膜的光致发光峰值强度随掺铒浓度呈现近Gauss形状变化,而最佳镱铒共掺样品的光致发光峰值强度随掺铒浓度呈现了倒Gauss形状变化.     

热退火对SiO2：Er薄膜发光特性的影响

利用离子注入法制备SiO₂:Er样品,并在不同温度下进行退火处理。通过微区拉曼光谱、吸收光谱、X射线光电子能谱等手段对其进行结构表征,并进行了室温和变温的光致发光特性研究,得到了可见区和红外区的光致发光。其中,⁴S_3/2→⁴I_15/2的发光强度随温度的升高,先增强后减弱,呈现出反常的温度淬灭效应,此现象是由Er³⁺与SiO₂的缺陷之间的能量传递造成的。     

退火对非故意掺杂4H-SiC外延材料386 nm和388 nm发射峰的影响

10 K条件下,采用光致发光(PL)技术研究了不同退火处理后非故意掺杂4H-SiC外延材料的低温PL特性.结果发现,在370—400 nm范围内出现了三个发射峰,能量较高的峰约为3.26 eV,与4H-SiC材料的室温禁带宽度相当.波长约为386 nm和388 nm的两个发射峰分别位于~3.21 eV和~3.19 eV,与材料中的N杂质有关.当退火时间为30 min时,随退火温度的升高,386 nm和388 nm两个发射峰的PL强度先增加后减小,且退火温度为1573 K时,两个发射峰的PL强度均达到最大. 关键词： 光致发光 退火处理 能级 4H-SiC     

Luminescence enhancement by hydrogenation of Si:Er,O

Erbium (Er)- and oxygen (O)-doped Cz–Si was additionally doped with hydrogen, using plasma enhanced chemical vapour deposition. Photoluminescence (PL) spectra show a large enhancement especially for samples treated with solid phase epitaxy before hydrogenation and annealing at 900°C later. Secondary ion mass spectroscopy measurements give evidence for an enhanced diffusion of O and Er at this temperature towards the surface. Etching shows that the PL does not stem from the heavily doped surface layer but from a deeper region with lower Er concentration. This conclusion is supported by the appearance of the so-called “cubic” centre with low solubility. Comparing the PL yield of the hydrogenated samples to that of samples with similar Er volume concentration but without hydrogenation still gives a large enhancement. We thus conclude that hydrogen can enhance the solubility of the cubic centre in Si:Er,O.     

掺饵氢化非晶氧化硅1.54μm发光性质的研究

采用等离子体增强化学汽相沉积技术生长不同氧含量的氢化非晶氧化硅薄膜(a-SiO_{x∶H),离子注入铒及退火后在室温观察到很强的光致发光.当材料中氧硅含量比约为1和 1.76时,分别对应77Ｋ和室温测量时最强的1.54μm光致发光.从15到250Ｋ的变温实验显示 出三个不同的强度与温度变化关系,表明氢化非晶氧化硅中铒离子的能量激发和发光是一个 复杂的过程.提出氢化非晶氧化硅薄膜中发光铒离子来自于富氧区,并对实验现象进行了解 释.氢化非晶氧化硅中铒发光的温度淬灭效应很弱.从15到250Ｋ,光致发光强度减弱约1/2. 关键词： 铒 光致发光 氧含量}     

Green Emitting Cerium Doped CaS Whiskers Grown by Solid State Diffusion Method

Undoped and cerium doped Calcium sulfide (CaS) phosphors were synthesized using solid state diffusion method. The X-ray diffraction pattern revealed that both undoped and doped CaS crystallites have cubic structure with average crystallite size varying from 20 to 30 nm. Scanning electron micrographs indicated that Ce doped CaS phosphors were composed of whiskers with different dimensions and orientations. The optical properties of undoped and Ce doped particles were characterized using Photoluminescence (PL) and UV-Vis absorption spectroscopy. The PL emission spectrum of cerium doped CaS phosphors for an excitation wavelength 465 nm showed a main peak at 500 nm and a shoulder peak at 556 nm due to 5d?→?4f transition in Ce³⁺ ions. The variation of PL intensity with cerium concentration was investigated and the maximum PL intensity was obtained for a doping concentration of 3 wt.%. The optical band gap of the samples was estimated from the diffuse reflectance spectrum and was found to increase with increase in cerium concentration. The enhanced optical properties of these phosphors can be exploited in various optoelectronic devices including displays and bioimaging techniques.     

MBE-grown Si: Er light-emitting structures: Effect of epitaxial growth conditions on impurity concentration and photoluminescence

The technology and properties of light-emitting structures based on silicon layers doped by erbium during epitaxial MBE growth are studied. The epitaxial layer forming on substrates prepared from Czochralski-grown silicon becomes doped by oxygen and carbon impurities in the process. This permits simplification of the Si: Er layer doping by luminescence-activating impurities, thus eliminating the need to make a special capillary for introducing them into the growth chamber from the vapor phase. The photoluminescence spectra of all the structures studied at 78 K are dominated by an Er-containing center whose emission line peaks at 1.542 μm. The intensity of this line measured as a function of the substrate and erbium dopant source temperatures over the ranges 400–700°C and 740–800°C, respectively, exhibits maxima. The edge luminescence and the P line observed in the PL spectra are excited predominantly in the substrate. The erbium atom concentration in the epitaxial layers grown at a substrate temperature of 600°C was studied by Rutherford proton backscattering and exhibits an exponential dependence on the erbium source temperature with an activation energy of ～2.2 eV.     

EXAFS analysis of Er sites in Er–O and Er–F co-doped crystalline Si

We present extended X-ray absorption fine structure (EXAFS) and photoluminescence (PL) analyses of Er–O and Er–F co-doped Si. Samples were prepared by multiple implants at 77 K of Er and co-dopant (O or F) ions resulting in the formation of a2 μm thick amorphous layer uniformly doped with 1×10¹⁹ Er/cm³ and 3×10¹⁹ O/cm³, 1×10²⁰ O/cm³ or 1×10²⁰ F/cm³. EXAFS measurements show that the local environment of the Er sites in the amorphous layers consists of 6 Si first neighbors. After epitaxial regrowth at 620°C for 3 h, Er is fully coordinated with 8 F ions in the Er–F samples, while Si and O ions are concomitantly present in the first shell of O co-doped samples. Post regrowth thermal treatments at 900°C leave the coordination unchanged in the Er+F, while the Er+O (ratio 1 : 10) doped samples present Er sites with a fully O coordinated shell with an average of 5 O atoms and 4 O atoms after 30 s and 12 h, respectively. We have also found that the fine structure and intensity of the high-resolution PL spectra are strongly dependent on the Er-impurity ratio and on thermal process parameters in the Er–O co-doped samples, while this is not observed for the F-doped samples. The most intense PL response at 15 K was obtained for the 1 : 3 E : O ratio, suggesting that an incomplete O shell around Er is particularly suitable for optical excitation.