共查询到20条相似文献,搜索用时 15 毫秒
1.
《Chinese Journal of Lasers》1998,(2)
AmplifiedSpontaneousEmisionofK2YelowBandExcimerandItsGainMeasurementbye┐beam┐pumpingXINGDa1)WANGQi2)TANShici1)(1)Instituteof... 相似文献
2.
ResearchonInjection┐seededβ┐BaB2O4OpticalParametericOscilatorZHAOYonghuaHEHuijiuanWANGZhijiang(ShanghaiInstituteofOpticsandFi... 相似文献
3.
We report a very high signal gain of 1.13 × 107 at a low pump intensity of 260 MW/cm2 in a two-stage optical parametric chirped-pulse amplifier (OPCPA), which is used as a pre-amplifier for a short-pulse front-end Nd: glass high-energy laser system. A signal energy of 0.17 nJ was amplified to 2 mJ with a central wavelength of 1053 nm and a repetition rate of 10 Hz using the OPCPA with a 15 mm-long BBO crystal at optical parametric amplifier (OPA) stage 1 and a 12 mm-long BiBO crystal at OPA stage 2. 相似文献
4.
Using a first-principles approach based on density functional theory,this paper studies the electronic and dynamical properties of β-V2O5.A smaller band gap and much wider split-off bands have been observed in comparison with αV2O5.The Ramanand infrared-active modes at the Γ point of the Brillouin zone are evaluated with LO/TO splitting,where the symbol denotes the longitudinal and transverse optical model.The nonresonant Raman spectrum of a βV2O5 powder sample is also computed,providing benchmark theoretical results for the assignment of the experimental spectrum.The computed spectrum agrees with the available experimental data very well.This calculation helps to gain a better understanding of the transition from αto β-V2O5. 相似文献
5.
This paper reports that/3-Ga2O3 nanorods have been synthesized by ammoniating Ga2O3 films on a V middle layer deposited on Si(111) substrates. The synthesized nanorods were confirmed as monoclinic Ga2O3 by x-ray diffraction,Fourier transform infrared spectra. Scanning electron microscopy and transmission electron microscopy reveal that the grown β-Ga2O3 nanorods have a smooth and clean surface with diameters ranging from 100 nm to 200 nm and lengths typically up to 2μm. High resolution TEM and selected-area electron diffraction shows that the nanorods are pure monoclinic Ga2O3 single crystal. The photoluminescence spectrum indicates that the Ga2O3 nanorods have a good emission property. The growth mechanism is discussed briefly. 相似文献
6.
Huizhao Zhuang Shiying Zhang Xiaokai Zhang Chengshan Xue Baoli Li Dexiao Wang Jiabing Shen 《Applied Surface Science》2008,254(10):3057-3060
A novel method was applied to prepare β-Ga2O3 nanorods. In this method, β-Ga2O3 nanorods have been successfully synthesized on Si(1 1 1) substrates through annealing sputtered Ga2O3/Mo films under flowing ammonia at 950 °C in a quartz tube. The as-synthesized nanorods are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR). The results show that the nanorod is single-crystalline Ga2O3 with monoclinic structure. The β-Ga2O3 nanorods are straight and smooth with diameters in the range of 200-300 nm and lengths typically up to several micrometers. The growth process of the β-Ga2O3 nanorods is probably dominated by conventional vapor-solid (VS) mechanism. 相似文献
7.
R. Jangir Tapas GanguliPragya Tiwari S. PorwalHimanshu Srivastava S.K. RaiB.Q. Khattak S.M. Oak 《Applied Surface Science》2011,257(22):9323-9328
β-Ga2O3 nanostructures including nanowires, nanoribbons and nanosheets were synthesized via thermal annealing of gold coated GaAs substrates in N2 ambient. GaAs substrates with different dopants were taken as the starting material to study the effect of doping on the growth and photoluminescence properties of β-Ga2O3 nanostructures. The nanostructures were investigated by Grazing Incident X-ray Diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy, Energy Dispersive X-ray Spectroscopy, room temperature photoluminescence and optical absorbance. The selected area electron diffraction and High resolution-TEM observations suggest that both nanowires and nanobelts are single crystalline. Different growth directions were observed for nanowires and nanoribbons, indicating the different growth patterns of these nanostructures. The PL spectra of β-Ga2O3 nanostructures exhibit a strong UV-blue emission band centered at 410 nm, 415 nm and 450 nm for differently doped GaAs substrates respectively. A weak red luminescence peak at 710 nm was also observed in all the samples. The optical absorbance spectrum showed intense absorption features in the UV spectral region. The growth and luminescence mechanism in β-Ga2O3 nanostructures are also discussed. 相似文献
8.
Jianguo Zhao Weiying ZhangErqing Xie Ziwei MaAke Zhao Zhaojun Liu 《Applied Surface Science》2011,257(11):4968-4972
Eu3+-doped β-Ga2O3 nanofibers were fabricated by electrospinning. The influence of Eu3+ concentration on the photoluminescence properties of the obtained nanofibers was investigated. The morphology and structure of β-Ga2O3:Eu3+ were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and Raman spectra. The diameter of the Eu3+-doped β-Ga2O3 nanofibers was in the range of 180-300 nm. When the β-Ga2O3:Eu3+ nanofibers were excited by 325 nm wavelength, the main emission peak of the samples was 620 nm (5D0→7F2), which corresponded to a typical red emission (5D0→7Fj (j = 1, 2, 3, 4) intra-4f transitions of Eu3+ ions). In addition, the concentration quench effect and energy transfer mechanism in β-Ga2O3:Eu3+ were also discussed. 相似文献
9.
Yong Liu Ruiqing Chu Zhijun Xu Huiqin Lv Liming Wu Yizheng Yang Guorong Li 《Physica B: Condensed Matter》2012,407(13):2573-2577
Dense K4CuNb8O23 (KCN) modified 0.948K0.5Na0.5NbO3–0.052LiSbO3 (KNNLS) ceramics were prepared by conventional solid state reaction method. The effect of addition of K4CuNb8O23 liquid phase sintering aid on the phase structure and electrical properties of ceramics was studied. Results showed that K4CuNb8O23 induced a perovskite structure transition from coexistence of orthorhombic and tetragonal phases to orthorhombic symmetry. The addition of K4CuNb8O23 promoted the sintering of KNNLS ceramics. In particular, the K4CuNb8O23 addition to the KNNLS greatly improved the mechanical quality factor Qm value. The ceramics with x=0.8 sintered at 1090 °C possess the optimum properties (Qm=192, d33=135 pC/N, tan δ=0.024 and kp=0.357). These results indicate that the ceramic is a promising candidate for lead-free high-power piezoelectric devices, such as piezoelectric actuators, transformers and filter materials. 相似文献
10.
Sb-doped β-Ga2O3 crystals were grown using the optical floating zone(OFZ) method.X-ray diffraction data and X-ray rocking curves were obtained,and the results revealed that the Sb-doped single crystals were of high quality.Raman spectra revealed that Sb substituted Ga mainly in the octahedral lattice.The carrier concentration of the Sb-doped single crystals increased from 9.55 × 1016 to 8.10 × 1018 cm-3,the electronic mobility depicted a dec... 相似文献
11.
Structures and magnetic anisotropy of β-Mn2V2O7 crystals synthesized by the molten salt method 下载免费PDF全文
β-Mn2V2O7 crystals with strip shape are successfully prepared by the molten salt method in a closed crucible,and are characterized by x-ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM),selected area of electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM).The results indicate that the sample is of the β-Mn2V2O7 crystal with monoclinic symmetry,level natural cleavage facets and directional growth.Magnetic properties are measured by vibration sample magnetometry (VSM) at room temperature,and the magnetic hysteresis loop indicates that the β-Mn2V2O7 has anti-ferromagnetic properties with low coercive force and remnant magnetization.The magnetic measurement results in different directions exhibit that the β-Mn2V2O7 has magnetic anisotropy,which is due to the fact that the magnetic interaction energy of the β-Mn2V2O7 is lowest only when the electron configuration is in a certain direction. 相似文献
12.
Effects of N-doping concentration on the electronic structure and optical properties of N-doped β-Ga2O3 下载免费PDF全文
The electronic structures and the optical properties of N-doped β-Ga2O3 with different N-doping concentrations are studied using the first-principles method.We find that the N substituting O(1) atom is the most stable structure for the smallest formation energy.After N-doping,the charge density distribution significantly changes,and the acceptor impurity level is introduced above the valence band and intersects with the Fermi level.The impurity absorption edges appear to shift toward longer wavelengths with an increase in N-doping concentration.The complex refractive index shows metallic characteristics in the N-doped β-Ga2O3. 相似文献
13.
14.
15.
Monodisperse Au-Fe 3 O 4 heterodimeric nanoparticles (NPs) were prepared by injecting precursors into a hot reaction solution.The size of Au and Fe 3 O 4 particles can be controlled by changing the injection temperature.UV-Vis spectra show that the surface plasma resonance band of Au-Fe 3 O 4 heterodimeric NPs was evidently red-shifted compared with the resonance band of Au NPs of similar size.The as-prepared heterodimeric Au-Fe 3 O 4 NPs exhibited superparamagnetic properties at room temperature.The Ag-Fe 3 O 4 heterodimeric NPs were also prepared by this synthetic method simply using AgNO 3 as precursor instead of HAuCl 4.It is indicated that the reported method can be readily extended to the synthesis of other noble metal conjugated heterodimeric NPs. 相似文献
16.
Jie ZhuJiang He Xiaoyan DuRuihua Lu Lizhen HuangXia Ge 《Applied Surface Science》2011,257(21):9056-9062
In this study, a kind of novel surface-functionalized magnetic nanoparticles was fabricated by the Fe3O4 nanoparticles surface modification with mono-6-deoxy-6-(p-tolylsulfonyl)-cyclodextrin (6-TsO-β-CD), which were employed to interact with uric acid and their behavior was investigated by electrochemical methods. The architecture has been characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA), which confirmed that cyclodextrins have been effectively functionalized on the surface of Fe3O4 nanoparticles. The analyses of vibration sample magnetometer (VSM) verified that the nanoparticles owned good magnetic property. The grafted β-cyclodextrin on the Fe3O4 nanoparticles contributed to as a modified electrode for detecting uric acid with cyclic voltammograms. Electrochemical results revealed that the new materials could exhibit excellent molecules recognition ability and show high electrochemical response. The new nanoparticles simultaneously had unique properties of magnetic nanoparticles and cyclodextrins through combining their individual distinct advantages. 相似文献
17.
Kenichiro Takakura Suguru Funasaki Isao Tsunoda Hidenori Ohyama Daisuke Takeuchi Toshiyuki Nakashima Mutsuo Shibuya Katsuya Murakami Eddy Simoen Cor Claeys 《Physica B: Condensed Matter》2012,407(15):2900-2902
A transparent electrode of Si doped β-Ga2O3 films for solar cells, flat panel displays and other devices, which consists of chemically abundant and ecological friendly elements of gallium and oxygen, was grown on silicon substrates by RF magnetron sputtering using sintered Ga2O3 and Si target. The Si composition in the β-Ga2O3 film is determined by electron dispersive X-ray spectroscopy. The X-ray photoelectron spectroscopy peak ratio of oxygen over gallium decreases with increasing Si content. It is concluded that Si substitutes for the Ga sites in the β-Ga2O3 film. 相似文献
18.
X.H. Wang F.B. Zhang K. Saito T. Tanaka M. Nishio Q.X. Guo 《Journal of Physics and Chemistry of Solids》2014
We study the electrical properties and emission mechanisms of Zn-doped β-Ga2O3 film grown by pulsed laser deposition through Hall effect and cathodoluminescence which consist of ultraviolet luminescence (UV), blue luminescence (BL) and green luminescence (GL) bands. The Hall effect measurements indicate that the carrier concentration increases from 7.16×1011 to 6.35×1012 cm−3 with increasing a nominal Zn content from 3 to 7 at%. The UV band at 272 nm is not attributed to Zn dopants and ascribed as radiative electron transition from conduction band to a self-trapped hole while the BL band is attributable to defect level related to Zn dopant. The BL band has two emission peaks at 415 and 455 nm, which are ascribed to the radiative electron transition from oxygen vacancy (VO) to valence band and recombination of a donor–acceptor pair (DAP) between VO donor and Zn on Ga site (ZnGa) acceptor, respectively. The GL band is attributed to the phonon replicas’ emission of the DAP. The acceptor level of ZnGa is estimated to be 0.26 eV above the valence band maximum. The transmittance and absorption spectra prove that the Zn-doped β-Ga2O3 film is a dominantly direct bandgap material. The results of Hall and cathodoluminescence measurements imply that the Zn dopant in β-Ga2O3 film will form an acceptor ZnGa to produce p-type conductivity. 相似文献
19.
用提拉法技术生长出了掺Bi的α-BaB2O4单晶并经过γ射线辐照.测定了样品在室温下的吸收光谱、发射光谱及荧光衰减曲线.在808 nm波长光的激发下,经γ射线辐照后的α-BaB2O4单晶中发现了中心波长为1139 nm、半高宽为113 nm的近红外宽带发光现象.讨论了辐照条件和退火处理对Bi离子发光的影响.对于其发光机理进行了初步的探讨.
关键词:
近红外宽带发光
2O4单晶')" href="#">α-BaB2O4单晶
辐照
退火处理 相似文献
20.
Q. Su 《Applied Surface Science》2009,255(7):4177-4179
β-V2O5 films were successfully prepared on silicon substrates by direct current (DC) reactive magnetron sputtering. X-ray diffraction (XRD), Raman spectra and field emission scan electron spectroscopy (SEM) were used to characterize the samples. Results revealed that the deposition temperature significantly influenced on the crystal structure of V2O5 films in the growth process. When the deposition temperature was below 500 °C, the sputtered film exhibited the α-V2O5 structure. However, β-V2O5 film was successfully obtained at 550 °C. High deposition temperature might provide V and O ions high mobility and energy in the reactive sputtering process, which induced the metastable β-V2O5 phase formed. The thermal stability of β-V2O5 film was studied by micro-Raman spectroscopy. The structure of sputtered β-V2O5 film was unstable under high temperature conditions (beyond 500 °C). 相似文献