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1.
利用直流磁控共溅射方法制备了GaN:Er薄膜.X射线衍射结果显示薄膜为纳米多晶结构,根据谢乐公式,计算得到了GaN薄膜晶粒的平均大小为58nm;透射电子显微镜结果显示为非晶基质中镶嵌了GaN纳米颗粒,尺寸在6—8nm之间;紫外可见谱结果表明在500—700nm的可见光范围内,薄膜的平均透过率大于80%,在紫外可见谱基础上,利用Tauc公式计算得到了纳米晶GaN薄膜的光学带隙为322eV;最后,测量了GaN:Er薄膜的室温光致发光谱,获得了Er3+离子在554nm处的强烈绿光发射.
关键词:
纳米晶GaN薄膜
3+掺杂')" href="#">Er3+掺杂
光学带隙
光致发光 相似文献
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利用直流磁控共溅射方法制备了GaN:Er薄膜.X射线衍射结果显示薄膜为纳米多晶结构,根据谢乐公式,计算得到了GaN薄膜晶粒的平均大小为5.8nm;透射电子显微镜结果显示为非晶基质中镶嵌了GaN纳米颗粒,尺寸在6-8nm之间;紫外可见谱结果表明在500-700nm的可见光范围内,薄膜的平均透过率大于80%,在紫外可见谱基础上,利用Tauc公式计算得到了纳米晶GaN薄膜的光学带隙为3.22eV;最后,测量了GaN:Er薄膜的室温光致发光谱,获得了Er3 离子在554nm处的强烈绿光发射. 相似文献
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对晶粒尺寸在4—80nm范围的纯SnO2纳米颗粒进行了拉曼散射研究.除了SnO2本征拉曼振动峰外,还有几个新的拉曼振动峰和波长在700nm左右的一个发光很强而且峰宽很大的荧光峰被观察到.结果所示,当纳米颗粒尺寸减小时,纳米SnO2颗粒的体相 特征拉曼峰变弱,而由缺陷,表面和颗粒尺寸引起的相关效应呈强势.晶粒尺寸在20nm左右是引起体相拉曼光谱变化的临界尺寸.晶粒尺寸在20nm以下,其体相拉曼峰的发生宽化和峰位移动,以及分别出现在位于571cm-1 的表面振动峰,位于351cm-1 处的界面峰和与表面吸附水分子及氢氧基团的N系列拉曼峰是纳米SnO颗粒的主要特征.这些结果反映了纳米颗粒的微结构变化与颗粒尺寸和表面效应以及它们之间相互作用的信息.
关键词:
2')" href="#">纳米SnO2
拉曼光谱
荧光光谱
水分子的吸附 相似文献
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利用Raman散射谱研究了GaN注Er以及Er+O共注样品的振动模,并讨论了共注入O对Er离子发光的影响. 在Raman散射谱中,对于注Er的GaN样品出现了300 cm-1和670 cm-1两个新的Raman峰,而对于Er+O共注样品,除了上述两个峰外,在360 cm-1处出现了另外一个新的峰,其中300 cm-1峰可以用disorder-activated Raman scattering (DARS)来解释,670 cm-1峰是由于与N空位相关的缺陷引起的,而360 cm-1峰是由O注入引起的缺陷络合物产生的. 由于360 cm-1模的缺陷出现,从而导致Er+O共注入GaN薄膜红外光致发光(PL)强度的下降.
关键词:
GaN
Er
Raman散射
光致发光 相似文献
7.
不同退火温度的ZrO_2 纳米颗粒光学声子和表面吸附分子的拉曼散射研究(英文) 总被引:2,自引:2,他引:0
本文对晶粒尺寸在5nm 1 μm范围的纯ZrO2 纳米颗粒进行了拉曼散射研究。除了ZrO2 本征拉曼振动峰外,还有几个新的拉曼振动模式被观察到。我们的结果显示当纳米颗粒尺寸减少时,纳米ZrO2 颗粒的体相特征拉曼峰变弱,而由缺陷,表面和颗粒尺寸引起的相关效应呈强势。晶粒尺寸在1 5纳米左右是引起体相拉曼光谱变化的临界尺寸。晶粒尺寸在1 5纳米以下,其体相拉曼峰发生宽化和峰位移动,以及分别出现在位于1 0 40cm- 1的表面振动峰和1 4个较弱的二阶振动模式。这些结果反映了纳米颗粒的微结构变化与颗粒尺寸和表面效应以及它们之间相互作用的信息 相似文献
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This paper reports that the Raman spectra have been recorded on the
metal-organic chemical vapour deposition epitaxially grown GaN
before and after the Mn ions implanted. Several Raman defect modes
have emerged from the implanted samples. The structures around
182 cm-1 modes are attributed to the disorder-activated Raman scattering, whereas the 361 cm-1 and 660 cm-1 peaks are assigned to nitrogen vacancy-related defect scattering. One additional peak at 280 cm-1 is attributed to the vibrational mode of gallium vacancy-related defects and/or to disorder activated Raman scattering. A Raman-scattering study of lattice recovery is also presented by rapid thermal annealing at
different temperatures between 700 °C and 1050 °C on Mn implanted GaN epilayers. The behaviour of peak-shape change and
full width at half maximum (FWHM) of the A1(LO) (733 cm-1) and EH2 (566 cm-1) Raman modes are explained on the basis of implantation-induced lattice damage in GaN epilayers. 相似文献
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The new apatite–silicate phosphor doped with Eu ions in Ba10(PO4)4(SiO4)2 matrix was synthesized through solid-state reaction. It was found that the as-synthesized phosphor displayed apparent mixture of band and line emission peaks giving rise to pseudo white light. The narrow emission bands peaking at 410 nm can be assigned to the 4f65d→4f7(8S7/2) transition of Eu2+ ions, and the other band at 507 nm is ascribed to anomalous fluorescent emission. One group of line emission peaking at 595 nm and 613 m were due to the 5D0→7F1 and 5D0→7F2 transition of Eu3+ ions. The occurrence of photostimulated luminescence and discrete emission lines in violet (410 nm), green (507 nm) and red (595 nm and 613 nm) colors indicate that this material has potential application in fields of white-light-emitting. 相似文献
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Copper-doped Na21(SO4)7F6Cl phosphor was synthesized via the conventional wet chemical method. The synthesis was carried using CuCl2 and Cu (NO3)2·3H2O as dopants in two different steps successively. The formation and phase purity of the compound were revealed by the X-ray diffraction pattern. Functional groups of the prepared phosphor were observed in the FT–IR spectrum. The emission along with excitation spectra were followed to explore the luminescence attributes. Photoluminescence (PL) emission spectrum of the material synthesized using CuCl2 as the dopant was observed at 358?nm due to 3dl0?3d94s transitions when excited around 247?nm for various copper concentrations. Efficient blue emissions were obtained at peaks 423 and 469?nm for materials synthesized using Cu (NO3)2·3H2O as the dopant, when monitored at 357?nm excitation. The Commission Internationale de I’Eclairage chromaticity coordinates for different copper concentrations were calculated for the emission around 423?nm. TL glow curves of Na21(SO4)7F6Cl:Cu phosphor for different dopant concentrations, irradiated with 100?Gy gamma dose, were studied and hence the trap parameters, namely order of kinetics (b), activation energy (E) and frequency factor (s) associated with the most intensive glow peak of Na21(SO4)7F6Cl:Cu phosphor were determined by using Chen’s Peak shape method. The results indicate that Na21(SO4)7F6Cl:Cu+ is a potential novel blue-emitting lamp phosphor and may be quite suitable for use in dosimetry of ionizing radiations. 相似文献
14.
XiaoBo Chen ZengFu Song JinGuang Wu N. Sawanoboi M. Ohtsuka YongLiang Li Jing Zhou Ce Wang JinYing Liu Qiang Tian Ping Sun HongMei Jing 《中国科学G辑(英文版)》2008,51(12):1868-1876
The ultraviolet upconversion luminescence of Tm3+ ions sensitized by Yb3+ ions in oxyfluoride nanophase vitroceramics when excited by a 975 nm diode laser was studied. An ultraviolet upconversion
luminescence line positioned at 363.6 nm was found. It was attributed to the fluorescence transition of 1D2→3H6 of Tm3+ ion. Several visible upconversion luminescence lines at 450.7 nm, (477.0 nm, 462.5 nm), 648.5 nm, (680.5 nm, 699.5 nm) and
(777.2 nm, 800.7 nm) were also found, which result respectively from the fluorescence transitions of 1D2→3F4, 1G4→3H6, 1G4→3F4, 3F3→3H6 and 3H4→3H6 of Tm3+ ion. The careful measurement and analysis of the variation of upconversion luminescence intensity F as a function of the 975 nm pumping laser power P prove that the upconversion luminescence of 1D2 state is partly a five-photon upconversion luminescence, and the upconversion luminescence of 1G4 state and 3H4 state are respectively the three-photon and two-photon upconversion luminescence. The theoretical analysis suggested that
the upconversion mechanism of the 363.6 nm 1D2→3H6 upconversion luminescence is partly the cross energy transfer of {3H4(Tm3+), 3F4(Tm3+), 1G4(Tm3+)→1D2(Tm3+)} and {1G4(Tm3+)→3F4(Tm3+), 3H4(Tm3+)→1D2(Tm3+)} between Tm3+ ions. In addition, the upconversion luminescence of 1G4 and 3H4 state results respectively from the sequential energy transfer {2F5/2(Yb3+)→2F7/2(Yb3+), 3H4(Tm3+)→1G4(Tm3+)} and {2F5/2(Yb3+) →2F7/2(Yb3+), 3F4(Tm3+)→3F2(Tm3+)} from Yb3+ ions to Tm3+ ions.
Supported by the National Natural Science Foundation of China (Grant No. 10674019) 相似文献
15.
采用固相法制备了红色LiM(M=Ca, Sr, Ba)BO3 : Re3+(Re=Eu, Sm)发光材料,研究了材料的发光性能。研究发现LiM(M=Ca, Sr, Ba)BO3 : Eu3+材料呈现多峰发射,最强发射分别位于610,615,613 nm处,分别监测这三个最强峰,所得激发光谱峰值位于369,400,470 nm。LiM(M=Ca, Sr, Ba)BO3 : Sm3+材料也呈多峰发射,分别对应Sm3+的4G5/2→6H5/2、4G5/2→6H7/2和4G5/2→6H9/2跃迁发射;分别监测602,599,597 nm三个最强发射峰,所得激发光谱峰值位于374,405 nm。研究了激活剂浓度对材料发射强度的影响,结果随激活剂浓度的增大,发射强度先增强后减弱,即,存在浓度猝灭效应。实验表明,加入电荷补偿剂Li+、Na+或K+均可提高LiM(M=Ca, Sr, Ba)BO3 : Re3+(Re=Eu, Sm)材料的发射强度。 相似文献
16.
Christian Merten Honggang Li Xuefang Lu Andreas Hartwig Laurence A. Nafie 《Journal of Raman spectroscopy : JRS》2010,41(12):1563-1565
Natural resonance electronic Raman optical activity (ROA) is observed for the first time. Coincidently, the first example of vibrational ROA enhanced by low‐lying electronic transition is reported. These new phenomena were measured using the rare‐earth complex Eu(tfc)3 (+)‐tris[3‐trifluoroacetyl‐D ‐camphorato]europium(III), where electronic resonance occurs between the 532‐nm laser excitation and the 7F1 → 5D1 transition of the Eu3+ metal center. Electronic Raman spectra involve the Raman transitions terminating on the low‐lying electronic states of Eu(tfc)3. The observed vibrational ROA spectra are enhanced relative to typical ROA spectra by the proximity of vibrational states of Eu(tfc)3 to its low‐lying electronic states with significant magnetic‐dipole character, whereas the parent vibrational Raman spectra do not appear to be resonance‐enhanced since the 532‐nm vibrational Raman spectrum has similar relative intensities to the corresponding Raman spectrum measured with 1064‐nm laser excitation. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
17.
A novel ligand with double sulfinyl groups, bis(benzylsulfinyl)methane, was synthesized by a new method and its two lanthanide
(III) complexes were synthesized and characterized by element analysis, molar conductivity, coordination titration analysis,
IR, TG-DSC, 1HNMR and UV spectra. The results indicated that the composition of these complexes was REL2.5(ClO4)3·3H2O (RE = Tb (III), Dy (III), L = C6H5CH2SOCH2SOCH2C6H5). The FT-IR results revealed that the perchlorate group was bonded with the lanthanide ion by the oxygen atoms, and the coordination
was bidentate. The fluorescent spectra illustrated that both the Tb (III) and Dy (III) complexes displayed characteristic
fluorescence in solid state, especially for the Tb (III) complex, the peak of 5D4 → 7 F5 of the Tb (III) ion in 544 nm was stronger than that of others. It indicated that the Tb (III) complex could emit purer green
fluorescence. By analysis fluorescence and phosphorescence spectra, it was found that the ligand had the advantage to absorb
energy and transfer it to the Tb (III) and Dy (III) ions. The phosphorescence spectra and fluorescence lifetimes of the complexes
were also measured. 相似文献
18.
Eutectic crystal of 0.5% Eu-doped 30LaAlO3–70Al2O3 (vol %) was prepared by micro-pulling down (μ-PD) technique under nitrogen atmosphere. Being excited at a wavelength of 320 nm, the crystal exhibited intense emission band with a maximum at 450 nm which is corresponding to 4f65d-4f7(8S7/2) transitions of Eu2+. The decay time and fluorescence quantum efficiency (QE) were determined to be about 475 ns and 60%, respectively. When alpha-ray excited the crystal, both Eu2+ 4f65d-4f7(8S7/2) and Eu3+ 4f6-4f6 (5D0-7F1,2) emission peaks were observed at 435 nm and 600 nm. By the pulse height spectra, the relative scintillation light yield of the crystal was about 4% compared with that of BGO commercial scintillator. 相似文献
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采用水热法合成了不同粒径的NaLa(MoO4)2∶Eu3+微晶.通过调节乙二醇浓度和反应时间,研究了NaLa(MoO4)2∶Eu3+微晶的形貌演变过程,在水热条件下180 ℃反应16 h获得了均一梭子形NaLa(MoO4)2∶Eu3+微晶,其晶粒长度约为2.0 μm.荧光光谱分析表明,Eu3+取代了NaLa(MoO4)2中La3+的格位, Eu3+在613 nm处红光发射(5D0–7F2跃迁)的浓度猝灭机理是电偶极-电四极相互作用,并发生了Eu3+( 5D1 ) + Eu3+(7F0 )→ Eu3+( 5D0 ) + Eu3+(7F3) 交叉弛豫,由此导致浓度猝灭.
关键词:
钼酸盐
水热法
稀土离子
发光 相似文献
20.
研究了Na5Tb(WO4)4单晶的高压发光规律,化学计量的Na5Tb(WO4)4基质发光单晶的发光来源于基质中高浓度Tb3+.用金刚石对顶砧显微光谱系统在0-4GPa范围内研究了Na5Tb(WO4)4的室温高压光谱,确定了各发射谱线的高压移动率.对Tb3+的5D4→7Fj(j=0,1,2,3,4,5),测到18条谱线高压移动率中除一条(5D4→7F2,常压峰值15509cm-1)蓝移外,都红移,红移率最大为-19.5cm-1/GPa(对应谱线5D4→7F4,常压峰值16876cm-1),与Tb3+在其它基质中相比,此移动率很大. 相似文献