共查询到18条相似文献,搜索用时 171 毫秒
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本文用深能级瞬态谱(DLTS)研究了GaP:N LED''s老化过程中深能级的变化。老化条件为:在正偏直流I=800mA下室温老化约650小时。发现GaP:N LED在老化前只存在两个能级△Ex和△Ea,而在老化的过程中观察到一个新能级△Eb逐渐形成。结合老化前后测量的LED''s发光光谱、光通、C-V特性及CLI、EBIC和SEI结果,讨论了深能级在GaP:N LED老化过程中对发光效率和退化特性的影响,认为△Eb是限制GaP:N LED发光效率及退化特性的无辐射复合中心。 相似文献
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在温度4.2K—110K范围内测量了GaP:Bi外延层的光致发光谱。发光谱中只出现Bi束缚激子辐射复合的谱线。由于Bi束缚激子的局域电子态与四周品格存在着相当强的耦合,晶格弛豫引起的多声子辐射复合非常明显,发射光谱呈现相当宽的橙色谱带,且声子伴线“丰富”并彼此重迭。实验结果表明:从4.2K—40K A类线与B类线并存,B类线强度随温度上升而减弱最终难于辨认,77K以上A类线支配着整个光谱。对复杂的发光光谱谱线进行了识别和分类,并借助于电子计算机用曲线拟合法对光谱进行精确分解,首次求出各系列的黄昆因子(Huang-Rhys factor)。较大数值的黄昆因子表明晶格弛豫是强的。 相似文献
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本文研究了Bi2Sr2CaCu2O8单晶(Tc=85K)、Bi2-xPbxSr2Ca2Cu3Oy单相(Tc=107K)和Bi(Pb)-Sr-Ca-Cu-O非晶体室温下20-720cm-1的Raman光谱.通过谱图的比较,我们认为456-466、631-650cm-1是高Tc氧化物的特征谱,它们与Cu-O链及Cu-O面上的强电子-声子耦合有关;掺Pb导致Bi(Pb)-O双层之间氧的分布改变,增强了Bi(Pb)-O双层之间的耦合,从而有助于提高超导转变温度Tc. 相似文献
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本文研究了20K-120K范围内GaP:N束缚激子发光与温度的关系,从实验结果发现,各发光中心之间存在着激子转移.初步分析表明,采用带带激发方式,激子转移会导致深束缚中心的热激活能拟合值偏高,其发光热猝灭是由于空穴的热离化所造成的. 相似文献
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用于光纤电流传感器的掺Bi稀土铁石榴石单晶生长与磁光性能 总被引:1,自引:0,他引:1
用熔盐法生长了两种Bi替代的高法拉第旋转、温度稳定的稀土铁石榴石磁光单晶Bi-HoYbIG和Bi-GdYIG,测试分析了其在近红外波段的磁光性能及其温度特性。Ho3-z-y,YbyiBixFe512(x=1.03,y=1.20)单晶的比法拉第旋转角为-891°/cm(λ=1.31μm)和-767°/cm(λ=1.55μm),Y3-z-yGdyBixFe5O12(x=0.46,y=0.24)单晶的值为-1067°/cm(λ=1.31μm)和-882°/cm(λ=1.55μm),两者都比纯YIG晶体高出许多。而且这两种晶体的法拉第旋转角随温度变化较小,在250~400K范围内,其温度灵敏度S分别为4. 60×10-4/K和4. 20×10-4/K。分析表明,Bi的掺入能大大提高晶体的法拉第旋转角,而yb3+、Gd3+等离子的掺入可以有效降低Bi3+替代磁光单晶的法拉第旋转的温度灵敏性,Bi-HoYbiG和Bi-GdYIG等磁光晶体非常适合作为高灵敏度、温度稳定的光纤电流传感器中的法拉第转子材料。 相似文献
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本文中,对吸附于纳米磷化镓(GaP)粉体表面的碱性品红拉曼光谱进行了研究。通过将吸附碱性品红与纯碱性品红晶体样品的拉曼光谱进行对比、分析可知,碱性品红在纳米GaP粉体表面发生了化学吸附。在吸附碱性品红样品的拉曼光谱中,位于1200~1320cm-1范围内的光谱特征表明可能有新的化学键(P-O-C+或Ga-O-C+)形成。碱性品红分子的中央碳正离子(C+)与GaP表面具有孤对电子的氧原子形成配位键。红外光谱结果表明,氧原子与纳米GaP粉体表面的磷原子或镓原子键合,以P-O,Ga-O或P-O-Ga形式存在于GaP表面。碱性品红分子的呼吸振动,N-苯环伸缩振动,以及苯环C-C伸缩振动散射强度与纯碱性品红晶体样品相比皆有所增强。N-苯环伸缩振动散射强度增加意味着N原子是除C+离子以外的另一个可以与GaP表面发生化学作用的活性中心,这种化学作用是由N原子与GaP表面存在共轭效应造成的。 相似文献
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纳米GaP材料Ga填隙缺陷的EPR实验观察 总被引:2,自引:0,他引:2
利用电子顺磁共振(EPR)技术对纳米GaP粉体材料的本征点缺陷进行了研究,结果表明:由EPR信息的g因子值(2.0027±0.0004)可以确定纳米GaP粉体材料存在Ga自填隙(Gai)本征缺陷;纳米GaP粉体EPR信号超精细结构消失,以及谱线线宽(ΔHPP)变窄等实验现象,可能是由纳米材料界面的无序性,以及缺陷原子和界面原子之间的电子交换造成的;在较低的测试温度范围内,升高温度引起纳米GaP材料发生晶界结构弛豫;当测试温度由100 K升高至423 K时,ΔHPP值和自由基浓度皆逐渐降低. 相似文献
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本文采用荧光窄化技术,对低组分的GaAs1-xPx:N(x=0.76,0.65)混晶材料中Nx束缚激子的声子伴线进行了研究.在低温下,选择激发Nx带时,我们得到了与GaP:N低温发光谱中类似的声子伴线结构.根据实验结果,给出了混晶中各种声子的能量.另外,对组分为x=0.76的GaAs1-xPx:N混晶样品,我们还首次观察并分析了多声子重现光谱. 相似文献
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Absorption and fluorescence of pure and isotopically substituted benzene crystals are reported for the range 4.2–20°K. The energy of electron- and vibron-phonon interactions and the probability of respective optical transitions are determined. The pronounced asymmetry of phonon sidebands of absorption and luminescence spectra is found. The kinetic analysis of isotopically impure crystal spectra gives the trap-trap energy transfer probability and the energy dependence of the electron-phonon coupling coefficient. 相似文献
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Optical measurements on the single crystals of the pseudobinary (ZnS)?(GaP) alloy were carried out. The band gap energy decreased more rapidly with increase in GaP concentration than that reported previously. The analysis of the absorption spectra for the crystals of up to 70 mole % GaP indicated a direct transition characteristic, and that the band gap becomes nearly equal to that of pure GaP at about 30 mole % GaP. The photoluminescence spectra observed at liquid nitrogen temperature could first be resolved into three kinds of emission band with Gaussian distribution. The peak energy of these bands were found to be independent of the band gap variation. Thus the observed peak energy shift with alloy composition was attributed to the variation of the emission intensity of each band. The band gap shrinkage and the origin of the photoluminescence spectra on the basis of a molecular orbital method were discussed. 相似文献
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The use of infrared quenching of photoluminescence to study the spectral dependence of the photoionization cross-section in
GaN doped with Zn, Hg, and Li is reported. It is shown that these impurities produce deep level centres 0.48 eV, 0.41 eV,
and 0.75 eV, respectively, above the valence band. In addition, excitation spectra are investigated for Zn and Li doped GaN,
giving values of 3.17 eV and 2.86 eV at 78 K for the energy distance of these levels from the conduction band. Finally, from
the temperature dependence of the excitation spectra, it is concluded that the levels are probably pinned to the valence band. 相似文献
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P. Migliorato G. Margaritondo P. Perfetti D. Margadonna 《Solid State Communications》1974,14(10):893-896
The increase of nitrogen concentration considerably affects the 1.6°K photoluminescence spectra of very heavily doped GaP:N. The first moment of the spectral emission shifts towards the red, while the ratio of the intensities of large-momentum phonon replicas of A, NN3 and NN1 lines to the no-phonon lines increases. An explanation is proposed in terms of overlapping of the bound exciton wave functions. 相似文献
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《Solid State Communications》1986,58(3):193-195
The defects introduced in p-type Zn doped GaP by beta particle irradiation, of 1 MeV average energy, at low temperatures are monitored by bridge measurements of capacitance and delectric losses of a capacitor. The results of measurements, between 15 and 65 K, are attributed, in two different temperature regimes, to a GaP capacitor with losses arising from (a) an a.c hopping conduction process, below 45 K, and (b) a band conduction, above 45 K. Electron irradiation affects both hopping and band conduction as well as the transition temperature. 相似文献