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Eu^(3+) doped K-Lu-F system optical materials: controlling synthesis, phase evolution, and optical properties

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Journal of Rare Earths 2015年第12期33卷 1261-1267页

作者：谢安刘小磊熊禹诚 School of Materials Science and Engineering Xiamen University of Technology

Using a hydrothermal method, by adjusting the reactant ratios, the hydrothermal temperatures, the hydrothermal time, and the pH values of prepared solutions, 1 mol.% Eu3＋ doped K-Lu-F system optical materials were synthesized under control. For com- parison, the sample was also synthesized by a co-precipitation method. The X-ray diffraction （XRD） results suggested that the final crystalline phases had great relations with the hydrothermal synthesis conditions. The field emission scanning electron microscopy （FE-SEM） images and the energy-dispersive spectroscopy （EDS） patterns indicated that the morphologies and the components of some representative samples also varied with the synthesis conditions. Eu3＋, acting as a probe, exhibited different optical proper- ties in the K-Lu-F system optical materials, which also indirectly proved the phase evolution of the final products. The results sug- gested that there were many crystalline phases with different symmetry in the K-Lu-F system. They would be good host matrices for the emitters.

关键词： hydrothermal phase evolution optical properties rare earths

Be-composition effect on structure,electronic and optical properties of Be_xZn_(1-x)O alloys

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Chinese Physics B 2011年第3期20卷 328-335页

作者：吕兵周勋令狐荣锋王晓璐杨向东 Institute of Atomic and Molecular Physics Sichuan University School of Physics and Electronic Science Guizhou Normal University College of Science Guizhou UniversityInstitute of New Optoelectronic Materials and Technology Guizhou University

This paper carries out first principles calculation of the structure, electronic and optical properties of BexZn1-xO alloys based on the density-functional theory for the compositions x = 0.0, 0.25, 0.5, 0.75, 1.0. The lattice constants deviations of alloys obey Vegard＇s law well. The BexZn1-xO alloys have the direct band gap （Г-Г） character, and the bowing coefficients axe less than the available theoretical values. Moreover, it investigates in detail the optical properties （dielectric functions, absorption spectrum and refractive index） of these ternary mixed crystals. The obtained results agree well with the available theoretical and experimental values.

关键词： alloys optical properties generalized gradient approximation,BexZn1-xO

Electronic and optical properties of O-Terminated Armchair Graphene Nanoribbons

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Chinese Journal of Chemical Physics 2016年第2期29卷 205-211,I0001页

作者：鲁道邦罗长更宋玉玲潘群娜濮春英南阳师范学院物理与电子工程学院南阳473061 南阳师范学院计算机与信息技术学院南阳473061

The structure, electromagnetic and optical properties of the O-terminated graphene nanorib- bons with armchair edge are studied using first-principles theory. The results show that the O-terminated armchair edge are more stable than the H-terminated ribbons and show metal- lic character. Spin-polarized calculations reveal that the antiferromagnetic state are more stable than the ferromagnetic state. The energy band and density of states analyses show that the O-terminated armchair edge are antiferromagnetic semiconductors. Because of the terminated 0 atoms, the dielectric function has an evident red shift and the first peak is the strongest with its main contribution derived from the highest valence band. The peaks of the dielectric function, reflection, absorption, energy loss are related to the transition of electrons. Our results suggest that the O-terminated graphene nanoribbons have potential applications in nanoelectronics, opto-electric devices.

关键词： First-principles Electronic properties optical properties O termination Graphene nanoribbons

Structural, electronic, and optical properties of ZnO_(1-x)Se_x alloys using first-principles calculations

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Chinese Physics B 2013年第8期22卷 581-588页

作者： Muhammad Rashid Fayyaz Hussain Muhammad Imran S A Ahmad N A Noor M U Sohaib S M Alay-e-Abbas Department of Physics Simulation Laboratory the Islamia University of Bahawalpur63100 Pakistan Department of Physics University of the Punjab Quaid-e-Azam Campus54590 Lahore Pakistan Lahore Development Authority 54590 Lahore Pakistan Department of Physics GC University FaisalabadAllama Iqbal Road Faisalabad 38000 Pakistan

The structural, electronic, and optical properties of binary ZnO, ZnSe compounds, and their ternary ZnOl_xSex alloys are computed using the accurate full potential linearized augmented plane wave plus local orbital （FP-LAPW ＋ lo） method in the rocksalt （B 1） and zincblende （B3） crystallographic phases. The electronic band structures, fundamental energy band gaps, and densities of states for ZnO1_xSex are evaluated in the range 0 〈 x 〈 1 using Wu-Cohen （WC） generalized gradient approximation （GGA） for the exchange-correlation potential. Our calculated results of lattice parameters and bulk modulus reveal a nonlinear variation for pseudo-binary and their ternary alloys in both phases and show a considerable deviation from Vegard＇s law. It is observed that the predicted lattice parameter and bulk modulus are in good agreement with the available experimental and theoretical data. We establish that the composition dependence of band gap is semi-metallic in B1 phase, while a direct band gap is observed in B3 phase. The calculated density of states is described by taking into account the contribution of Zn 3d, O 2p, and Se 4s, and the optical properties are studied in terms of dielectric functions, refractive index, reflectivity, and energy loss function for the B3 phase and are compared with the available experimental data.

关键词： density functional theory alloys structural electronic optical properties

One-pot synthesis and optical properties of In- and Sn-doped ZnO nanoparticles

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International Journal of Minerals,Metallurgy and Materials 2017年第4期24卷 455-461页

作者： Li-ping Wang Fu Zhang Shuai Chen Zi-heng Bai Department of Materials Physics and Chemistry School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Colloidal indium-doped zinc oxide (IZO) and tin-doped zinc oxide (ZTO) nanoparticles were successfully prepared in organic solution, with metal acetylacetonate as the precursor and oleylamine as the solvent. The crystal and optical properties were characterized by X-ray diffraction, UV−visible spectrophotometry, and fluorescence spectroscopy, respectively; the surface and structure morphologies were observed by scanning electron microscopy and transmission electron microscopy. The XRD patterns of the IZO and ZTO nanoparticles all exhibited similar diffraction peaks consistent with the standard XRD pattern of ZnO, although the diffraction peaks of the IZO and ZTO nanoparticles were slightly shifted with increasing dopant concentration. With increasing dopant concentration, the fluorescent emission peaks of the IZO nanoparticles exhibited an obvious red shift because of the difference in atomic radii of indium and zinc, whereas those of the ZTO nanoparticles exhibited almost no shift because of the similarity in atomic radii of tin and zinc. Furthermore, the sizes of the IZO and ZTO nanoparticles distributed in the ranges 20–40 and 20–25 nm, respectively, which is attributed to the difference in ionic radii of indium and tin. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

关键词： Crystal structure Doping (additives) Electron microscopy Fluorescence Fluorescence spectroscopy High resolution transmission electron microscopy Indium Metal nanoparticles Nanoparticles optical properties Scanning electron microscopy Semiconductor doping Tin Tin oxides Transmission electron microscopy X ray diffraction Zinc Zinc oxide

Electronic and optical properties of the zinc-blende structured LiZnN under pressure

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Chinese Physics B 2009年第7期18卷 2938-2944页

作者：常景兰俊卿艾琼陈向荣 School of Physical Science and Technology Sichuan University

The electronic and optical properties of the cubic zinc-blende （ZB） structured filled tetrahedral semiconductor α-LiZnN under pressure are investigated by using ab initio plane wave pseudopotential density functional theory method within the generalized gradient approximation （GGA）.The electronic band structure and the density of state under pressure are systematically *** basic optical constants,including the reflection and absorption spectra,the energy-loss function,the complex refractive index and the dielectric function,are calculated and analysed at different external *** results suggested that the ZB α-LiZnN is transparent in the partially ultra-violet to the visible light region,and it seems that the transparency is hardly affected by the pressure.

关键词： density functional theory electronic structure optical properties LiZnN

Effects of N-doping concentration on the electronic structure and optical properties of N-doped β-Ga_2O_3

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Chinese Physics B 2012年第6期21卷 431-436页

作者：张丽英闫金良张易军李厅 School of Physics Ludong University

The electronic structures and the optical properties of N-doped β-Ga2O3 with different N-doping concentrations are studied using the first-principles *** find that the N substituting O（1） atom is the most stable structure for the smallest formation *** N-doping,the charge density distribution significantly changes,and the acceptor impurity level is introduced above the valence band and intersects with the Fermi *** impurity absorption edges appear to shift toward longer wavelengths with an increase in N-doping *** complex refractive index shows metallic characteristics in the N-doped β-Ga2O3.

关键词： first-principles p-type β-Ga2O3 N-doped electronic structure optical properties

First-principles study of electronic and optical properties in wurtzite Zn_(1-x)Cu_xO

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Chinese Physics B 2010年第5期19卷 427-433页

作者：赵龙芦鹏飞俞重远刘玉敏王东林叶寒 Key Laboratory of Information Photonics and optical Communications(Beijing University of Posts and Telecommunications) Ministry of Education

We perform a first-principles simulation to study the electronic and optical properties of wurtzite Zn1-xCuxO. The simulations are based upon the Perdew-Burke-Ernzerhof form of generalised gradient approximation within the density functional theory. Calculations are carried out in different concentrations. With increasing Cu concentration, the band gap of Znl-xCuxO decreases due to the shift of valence band. The imaginary part of the dielectric function indicates that the optical transition between O2p states in the highest valence band and Zn 4s states in the lowest conduction band shifts to the low energy range as the Cu concentration increases. Besides, it is shown that the insertion of Cu atom leads to redshift of the optical absorption edge. Meanwhile, the optical constants of pure ZnO and Zn0.75Cu0.250, such as loss function, refractive index and reflectivity, are discussed.

关键词： density functional theory Cu-doped ZnO electronic structure optical properties

Electronic structures and optical properties of TiO_2:Improved density-functional-theory investigation

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Chinese Physics B 2012年第5期21卷 508-514页

作者：龚赛刘邦贵 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences

TiO2 has been recently used to realize high-temperature ferromagnetic *** fact,it has been widely used for a long time as white pigment and sunscreen because of its whiteness,high refractive index,and excellent optical ***,its electronic structures and the related properties have not been satisfactorily ***,we use Tran and Blaha＇s modified Becke-Johnson（TB-mBJ） exchange potential（plus a local density approximation correlation potential） within the density functional theory to investigate electronic structures and optical properties of rutile and anatase *** comparative calculations show that the energy gaps obtained from mBJ method agree better with the experimental results than that obtained from local density approximation（LDA） and generalized gradient approximation（GGA）,in contrast with substantially overestimated values from many-body perturbation（GW） *** for optical dielectric functions（both real and imaginary parts）,refractive index,and extinction coefficients as functions of photon energy,our mBJ calculated results are in excellent agreement with the experimental *** further analysis reveals that these excellent improvements are achieved because mBJ potential describes accurately the energy levels of Ti 3d *** results should be helpful to understand the high temperature ferromagnetism in doped *** approach can be used as a standard to understand electronic structures and the related properties of such materials as TiO2.

关键词： rutile anatase electronic structures optical properties