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1.
We study deep trapping states in Ce3+-doped garnet crystals with the composition (Lu,Y,Gd)3(Ga,Al)5O12, recently shown as having remarkably high light yield. We use thermally stimulated luminescence (TSL) technique above room temperature and determine the composition Gd3Ga3Al2O12 as the host showing the lowest concentration of traps. This host consistently manifests very low afterglow comparable to that of the standard BGO crystal. We also perform TSL glow peak analysis based on the initial rise technique to evaluate trap depth and other characteristics associated with TSL peaks. 相似文献
2.
V. V. Randoshkin N. N. Usmanov Yu. A. Koksharov V. I. Kozlov A. M. Saletzky N. N. Sysoev N. V. Vasilieva 《Technical Physics》2006,51(6):799-802
Ferromagnetic resonance in epitaxial (Bi,Lu)3(Fe,Ga)5O12 films grown on Gd3Ga5O12(210) substrates is investigated. The spectrum contains a number of peaks, the most intense of which is related to the bulk of the film and the transition layer at the film-substrate interface. Most of the film volume is characterized by reduced magnetic anisotropy. The azimuthal and polar dependences of the resonance field exhibit 180° symmetry. 相似文献
3.
The absorption spectra of Y3Ga5O12:(Fe3+), Y3Ga5O12:(Bi3+) and Y3Ga5O12:(Bi3+, Fe3+) are presented to 40,000 cm-1. Assignments are discussed and the transitions analysed in terms of their involvement in the large Faraday rotation observed in bismuth substituted iron garnets. 相似文献
4.
The X-band EPR spectra of Cr3+, Mn2+, and Fe3+ impurity ions in glasses of (CaO?Ga2O3?GeO2) system are investigated in the 77÷300 K temperature range. The experimental data analysis yields the following results: (i) Impurity chromium ions are incorporated into the (CaO?Ga2O3?GeO2) glasses network in Cr3+ (3d3,4F3/2) paramagnetic valence state only and occupy the strong distorted oxygen coordinated octahedral sites. (ii) For all activated and non-activated (CaO?Ga2O3?GeO2) glasses the iron impurity is present at concentration roughly 0.01 wt.%. Isotropic EPR signals atg eff=4.29 andg eff=2.00 are assigned to Fe3+ (3d5,6S5/2) ions in the sites with strong rhombic distortion and in the sites with nearly cubic symmetry respectively. (iii) The manganese EPR spectrum in (CaO?Ga2O3?GeO2) glasses is weakly dependent on temperature, doping procedure as well as manganese concentration. EPR spectra of impurity manganese ions in glasses with Ca3Ga2Ge3O12 and Ca3Ga2Ge4O14 compositions are virtually identical and belong to Mn2+ (3d5,6S5/2) ions. Impurity manganese ions are incorporated into the (CaO?Ga2O3?GeO2) glass network as isolated Mn2+ centres and clusters of Mn2+ ions. 相似文献
5.
V. V. Randoshkin N. V. Vasil’eva V. G. Plotnichenko Yu. N. Pyrkov S. V. Lavrishchev M. A. Ivanov A. A. Kiryukhin A. M. Saletskii N. N. Sysoev 《Physics of the Solid State》2004,46(6):1030-1036
Epitaxial films of composition (Gd,Nd)3Ga5O12 or (Gd,Y,Nd)3Ga5O12 with a neodymium content varying from 0.3 to 15 at. % are grown by liquid-phase epitaxy from a supercooled PbO-B2O3-based solution melt on Gd3Ga5O12(111) substrates. The optical absorption spectra of the epitaxial films grown are measured in the wavelength range 0.2–1.0 µm. The results of interpreting the absorption bands observed in the spectra are used to construct the energy level diagrams of Nd3+ and Gd3+ ions in the matrices of the epitaxial films. 相似文献
6.
利用Sol-Gel法在Pt/Ti/SiO2/Si衬底上制备出Bi4Ti3O12和Bi3.25La0.75Ti3O12薄膜,研究了La掺杂对Bi4Ti3O12薄膜的晶体结构、铁电性能和疲劳特性的影响,发现La掺杂没有改变Bi4Ti3O12薄膜的基本晶体结构,并且提高了Bi4Ti3O12铁电薄膜的剩余极化值和抗疲劳性能,对La掺杂改善Bi4Ti3O12铁电薄膜性能的机理进行了讨论.
关键词:
铁电性能
4Ti3O12薄膜')" href="#">Bi4Ti3O12薄膜
3.25La0.75Ti3O12薄膜')" href="#">Bi3.25La0.75Ti3O12薄膜
sol-gel法
La掺杂 相似文献
7.
V. V. Randoshkin V. I. Kozlov Yu. A. Koksharov A. M. Saletskiĭ N. N. Sysoev N. N. Usmanov 《Technical Physics》2007,52(4):495-497
It is shown that the ferromagnetic resonance spectrum in (Bi,Tm)3(Fe,Ga)5O12 films grown in Gd3Ga5O12(210) substrates has a single peak. The azimuthal and polar dependences of the resonance field possess 180° symmetry. The angular dependences of the ferromagnetic resonance line width and intensity are studied. 相似文献
8.
G. Cabello L. Lillo F. Cabrera B. Chornick 《Journal of Physics and Chemistry of Solids》2011,72(10):1170-1174
We report the photochemical method to synthesize Ga2O3-Dy3+-Co3+ and Ga2O3-Dy3+-Cr3+ thin films. X-ray photoelectron spectroscopy, X-ray diffraction and photoluminescence were used to characterize the products. These analyses revealed that as-deposited and annealed films are amorphous. The optical characterization of the films showed that these are highly transparent in the visible spectrum but decrease significantly with doped and co-doped films. Under the excitation of UV light (254 nm) the doped films (Ga2O3-Dy3+) show the characteristic emissions of Dy3+ at 500, 575, 594, 605 and 652 nm corresponding to 4F9/2→6HJ ( J=15/2, 13/2 and 11/2) transitions but the emissions decrease with the co-doped films (Ga2O3-Dy3+-M3+, where M=Cr or Co); a possible emission mechanism and energy transfer have been proposed. 相似文献
9.
V. Venkatramu D. Falcomer A. Speghini M. Bettinelli C.K. Jayasankar 《Journal of luminescence》2008,128(5-6):811-813
The concentration-dependent luminescence properties of sol–gel-derived nanocrystalline Lu3(1?x)Er3xGa5O12 powders (where x=0.01, 0.05 and 0.1) have been studied. Laser-excited luminescence spectra, emission decays and upconversion luminescence of Er3+-doped Lu3Ga5O12 nanocrystalline samples have been measured. The decay curve of the (2H11/2,4S3/2) emission exhibits a non-exponential behavior presumably due to cross-relaxation process. Moreover, near-infrared to visible upconversion luminescence has been observed in the green region for 1.0 mol% Er3+ ions in Lu3Ga5O12 nanocrystals upon 815 nm excitation. The power dependence of the anti-Stokes luminescence suggests that upconversion is probably achieved through the sequential absorption of two photons. To the best of our knowledge, this is the first report on the preparation and optical properties of Er3+-doped Lu3Ga5O12 in the form of nanocrystalline powders. 相似文献
10.
Xing Li Hong-Liang Lu Hong-Ping Ma Jian-Guo Yang Jin-Xin Chen Wei Huang Qixin Guo Ji-Jun Feng David Wei Zhang 《Current Applied Physics》2019,19(2):72-81
Thin Ga2O3 films were grown on Si (100) using trimethylgallium (TMG) and oxygen as the precursors through plasma-enhanced atomic layer deposition. The depositions were made over a temperature range of 80–250?°C with a growth per cycle of around 0.07 nm/cycle. Surface self-saturating growth was obtained with TMG pulse time ≥20?ms?at a temperature of 150?°C. The root mean square surface roughness of the obtained Ga2O3 films increased from 0.1?nm to 0.3?nm with increasing the growth temperature. Moreover, the x-ray photoelectron spectroscopy analysis indicated that the obtained film was Ga-rich with the chemical oxidation states Ga3+ and Ga1+, and no carbon contamination was detected in the films after Ar+ sputtering. The electron density of films measured by x-ray reflectivity varied with the growth temperature, increasing from 4.72 to 5.80?g/cm3. The transmittance of Ga2O3 film deposited on a quartz substrate was obtained through ultraviolet visible (UV–Vis) spectroscopy. An obvious absorption in the deep UV region was demonstrated with a wide band gap of 4.6–4.8?eV. The spectroscopic ellipsometry analysis indicated that the average refractive index of the Ga2O3 film was 1.91?at 632.8?nm and increased with the growth temperature due to the dense structure of the films. Finally, the I-V and C-V characteristics proved that the Ga2O3 films prepared in this work had a low leakage current of 7.2?×?10?11 A/cm2 at 1.0?MV/cm and a high permittivity of 11.9, suitable to be gate dielectric. 相似文献
11.
The temperature‐dependent Raman spectra of ferroelectric Bi4−xNdxTi3O12(x = 0, 0.5, 0.85) single crystals were recorded from 100 to 800 K. It was found that there is a critical Nd content x0 between 0.5 and 0.85. The Nd3+ ions prefer to replace Bi3+ ions in pseudo‐perovskite layers when x < x0, while they might begin to incorporate into (Bi2O2)2+ layers when x ≥ x0. Nd substitution leads to a decrease in the ferroelectric–paraelectric transition temperature (Tc). A monoclinic distortion of orthorhombic structure occurs in Bi4Ti3O12 crystals at temperatures below 200 K. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
12.
The complete diagonalisation (of energy matrix) method is applied in this paper to calculate together the optical and electron paramagnetic resonance (EPR) spectral data for Cr3+ ion at the trigonal Ga3+ site of Y3Ga5O12 crystal. The method is founded on the two-spin-orbit-parameter model where in addition to the contributions from the spin-orbit parameter of central dn ion (i.e., one-spin-orbit-parameter model) in the traditional crystal field theory, those from the spin-orbit parameter of ligand ion via covalence effect is also considered. The calculated results propose that by using only four adjustable parameters, the 12 observed spectral data (nine optical band positions and three EPR parameters g//, g⊥ and D) in Y3Ga5O12: Cr3+ are reasonably explained. The impurity-induced local lattice distortion of Cr3+ in Y3Ga5O12 crystal is also estimated through the calculations. The results are discussed. 相似文献
13.
The timing characteristics of scintillation response of Czochralski-grown Gd3Al2Ga3O12:Ce and Gd3Al2.6Ga2.4O12:Ce single crystals were compared. The photoelectron yield, scintillation decay times, and coincidence time resolution were measured. At 662 keV γ-rays, the photoelectron yield of 6200 phe MeV−1 obtained for Gd3Al2Ga3O12:Ce is higher than that of 4970 phe MeV−1 obtained for Gd3Al2.6Ga2.4O12:Ce, while an inferior energy resolution of the former (7.2% vs. 5.6%) is observed. Scintillation decays are approximated by sum of exponentials with the dominant fast component decay time and its relative intensity of 89 ns (73%) for Gd3Al2Ga3O12:Ce and 136 ns (69%) for Gd3Al2.6Ga2.4O12:Ce. The coincidence time resolution obtained for Gd3Al2Ga3O12:Ce is superior than that of Gd3Al2.6Ga2.4O12:Ce. The normalized time resolution was also discussed in terms of a number of photoelectrons and decay characteristics of the light pulse. 相似文献
14.
V. V. Randoshkin N. V. Vasil’eva A. V. Vasil’ev V. G. Plotnichenko S. V. Lavrishchev A. M. Saletskii K. V. Stashun N. N. Sysoev A. N. Churkin 《Physics of the Solid State》2001,43(9):1659-1664
The optical absorption due to impurity ions was studied in gadolinium-gallium garnet single crystal films with a stoichiometric composition Gd3Ga5O12 grown by liquid-phase epitaxy from a supercooled PbO-B2O3 solution melt on (111)-oriented Gd3Ga5O12 substrates. 相似文献
15.
G. B. Scott D. E. Lacklison J. L. Page J. Hewett 《Applied Physics A: Materials Science & Processing》1976,9(1):71-77
The absorption (α) and Faraday rotation (θ) spectra of 14 garnets belonging to the series Bi
x
Sm3-x
Fe5-y
Ga
y
O12 (0<x<1.05, 0.8<y<1.15) have been measured between 15 000 cm−1 and 19 000 cm−1. The figure of merit (θ/α) at 17 850 cm−1 (560 nm) increases linearly with increasing bismuth concentration up tox∼0.6 where it begins to increase less rapidly. For operation of magneto-optic display devices at 17 850 cm−1 there is no advantage in using garnets in this series withx>0.8. The Faraday rotation at 17 850 cm−1 increases linearly with bismuth concentration whereas the absorption coefficient increases more rapidly. The presence of
Bi3+ increases the intensity of all Fe3+ pair transitions in the garnet system as a result of the increased superexchange induced by Bi3+. This is in keeping with the observation that the intensity of the6A1g
(S)→4T1g
(G) transition in (RE)3Fe5O12 (RE=Er, Y, Dy, Gd, Eu) increases on traversing the above RE series as do the Curie temperatures of these iron garnets. 相似文献
16.
S.D. Bu 《Solid State Communications》2005,133(10):671-674
Lanthanum-substituted bismuth titanate, Bi3.5La0.5Ti3O12 (i.e., x=0.5 in Bi4−xLaxTi3O12), thin films have been grown on Pt/Ti/SiO2/Si substrates using pulsed laser deposition. The frequency dependence of the real part ε′(ω) and the imaginary part ε″(ω) of the dielectric constant has been studied. The ε′(ω) does not show any sudden change within the frequency range of 102-106 Hz. In contrast, the ε″(ω) shows a large dispersion as frequency decreases. The observed relaxation behavior in ε″(ω) can be explained in terms of a migration of oxygen vacancies in (Bi2O2)2+ layers, not in Bi2Ti3O10 perovskite layers. 相似文献
17.
制备了Tm3+(8.0mol%)掺杂(77-x)GeO2-xGa2O3-8Li2O-10BaO-5La2O3(x=4,8,12,16)系列玻璃.系统地研究了Ga2O3从4mol%变化到16mol%时,玻璃的光谱性质与热学性质的变化规律.差热分析表明,随着Ga2O3含量的增加,锗酸盐玻璃的热稳定性增加.运用Judd-Ofelt(J_O)理论计算得到了Tm3+在不同Ga2O3含量的GeO2-Ga2O3-Li2O-BaO-La2O3玻璃中的J-O强度参数(Ω2,Ω4,Ω6)及Tm3+各激发能级的自发跃迁概率、荧光分支比以及辐射寿命等光谱参量.在808nm激光二极管的激发下,测试并分析了Ga2O3对Tm3+荧光光谱特性的影响.随着Ga2O3从4mol%增加到16mol%,Tm3+在1.8μm处的荧光强度呈现先减弱后增强的特性.当Ga2O3含量大约在12mol%时,Tm3+在1.8μm处的荧光强度最弱,受激发射截面达到最小.还初步讨论了Ga2O3对玻璃结构与光谱参数的影响规律.
关键词:
3+掺杂锗酸盐玻璃')" href="#">Tm3+掺杂锗酸盐玻璃
光谱性能
Judd-Ofelt参数
热稳定性 相似文献
18.
Xipu He Junli Huang Liya Zhou Qi Pang Fuzhong Gong 《Central European Journal of Physics》2012,10(2):514-518
A series of new red phosphors, MZr2(PO4)3:Eu3+; Bi3+ (M=Na; K), were synthesized using the solidstate reaction method, and their photoluminescence spectra were measured. The
MZr2(PO4)3:Eu3+; Bi3+ (M=Na; K) phosphors were efficiently excited by an ultraviolet (UV; 395 nm) source, and showed intense orange-red emission
at 595 nm. Further investigation of the concentration-dependent emission spectra indicated that the MZr2(PO4)3:Eu3+; Bi3+ (M=Na; K) phosphors exhibit the strongest luminescence intensity when y = 0.01 in NaZr2(0:95−y)(PO4)3:Eu0.103+, Bi2y
3+ and y = 0.09 in NaZr2(0.95−y)(PO4)3:Eu0.103+, Bi2y
3+, whereas the relative PL intensity decreases with increasing Bi3+ concentration due to concentration quenching. The addition of Bi3+ widens the excitation band of NaZr2(0.95−y)(PO4)3:Eu0.103+, Bi2y
3+ around 320 nm, which provides the useful idea of broadening the excitation band around 300–350 nm to fit the ultraviolet
chip. 相似文献
19.
Highly textured bismuth oxide (Bi2O3) thin films have been prepared using anodic oxidation of electrodeposited bismuth films onto stainless steel substrates. The Bi2O3 films were uniform and adherent to substrate. The Bi2O3 films were characterized for their structural and electrical properties by means of X-ray diffraction (XRD), electrical resistivity and dielectric measurement techniques. The X-ray diffraction pattern showed that Bi2O3 films are highly textured along (1 1 1) plane. The room temperature electrical resistivity of the Bi2O3 films was 105 Ω cm. Dielectric measurement revealed normal oxide behavior with frequency. 相似文献
20.
用高温熔融法制备了Bi离子掺杂浓度为1mol%的GeO-B2O3-Na2O (GBNB),GeO2-Al2O3-Na2O(GANB),GeO2-Al2O3-BaO(GABB)和GeO2-Al2O3-Y2O3(GAYB)玻璃.测定了样品玻璃的差热曲线、吸收、发射光谱及荧光衰减曲线.实验发现GBNB,GANB,GAYB,GABB的吸收边带逐步发生红移.由于这些吸收边带是由Bi3+的6s2电子到Bi5+ 6s0空轨道的跃迁引起.因此推断GBNB,GANB,GAYB,GABB玻璃中Bi5+离子的含量逐步增加.在GABB,GAYB,GANB三个样品中观察到发光中心约1220nm超宽带荧光发射.荧光强度从GABB,GAYB,GANB逐步减弱,荧光半高宽和荧光寿命逐步变小.这些超宽带的荧光归属为Bi5+离子的发光所致.从吸收与荧光光谱的变化,推断在GeO2-Al2O3玻璃中引入BaO,Y2O3组分有利于Bi5+离子的形成.讨论了BaO,Y2O3化学组分对Bi离子在玻璃中的价态影响的内在机理.
关键词:
5+离子')" href="#">Bi5+离子
超宽带发光
吸收带
荧光寿命 相似文献