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The Zn0.9Co0.1O films are fabricated by chemical solution deposition method. All the films have the ZnO wurtzite structure with a preferential orientation along the c-axis. The analysis of X-ray near-edge absorption spectroscopy and X-ray photoelectron spectroscopy indicates that the valence of Co is +2, and there are oxygen vacancies in Zn0.9Co0.1O films annealed in Ar atmosphere. Extended X-ray absorption fine structure results reveal that Co2+ ions have dissolved into ZnO and substituted for Zn2+ ions. Magnetization measurements show that the film annealed in Ar exhibits ferromagnetism which can be explained by the formation of bound magnetic polarons. 相似文献
3.
MgxZn1-xO材料是一种新型光电功能材料.采用溶胶凝胶法在石英玻璃上制备了Mg0.25Zn0.75O薄膜,理论结合实验研究了Mg0.25Zn0.75O薄膜的结构和光学性能.研究表明,石英玻璃衬底上Mg0.25Zn0.75O薄膜呈六方纤锌矿结构,薄膜均匀,平均粒径约为20nm.吸收光谱表明吸收带边始于3
关键词:
0.25Zn0.75O薄膜')" href="#">Mg0.25Zn0.75O薄膜
溶胶凝胶法
石英玻璃衬底
紫外发光 相似文献
4.
用脉冲激光沉积(PLD)法在不同温度的Si(111)衬底上成功制备了c轴择优取向的Mg005Zn095O薄膜.通过X射线衍射(XRD)和光致发光谱(PL)研究了衬底温度对Mg005Zn095O薄膜结构和发光特性的影响,探讨了薄膜的结晶质量与发光特性之间的关系.结果表明,在衬底温度为450℃时生长的Mg005Zn095O薄膜具有很好的c轴取向和较强的光致发光峰.室温下分别用激发波长为240,300和325nm的氙灯作为激发光源得到不同样品的PL谱,分析表明紫外发光峰和紫峰来源于自由激子的复合辐射且发光强度与薄膜的结晶质量密切相关,蓝绿发光峰与氧空位有关.此外,探讨了衬底温度影响紫外光致发光峰红移和蓝移的可能机理.
关键词:
005Zn095O薄膜')" href="#">Mg005Zn095O薄膜
PLD
衬底温度
光致发光 相似文献
5.
Sujeet Chaudhary Kanwal Preet Bhatti S.C. Kashyap 《Journal of magnetism and magnetic materials》2009,321(8):966-970
In the present paper, the preliminary investigations of a series of ZnO thin films co-doped with indium and cobalt with an objective to elucidate the correlation, if any, between the carrier concentration and the induced room temperature ferromagnetism (RTFM), are presented. The single-phasic (Zn99.5In0.5)1−xCoxO thin films are deposited by spray pyrolysis. The substitution of Zn2+ by Co2+ has been established by optical transmission analysis of these films. The films are ferromagnetic at room temperature; and the magnetization has higher value for indium and cobalt co-doped thin film as compared with Zn090Co0.1O thin film (having no indium). 相似文献
6.
NiZn ferrite/polyvinylpyrrolidone composite fibres were prepared by sol–gel assisted electrospinning.Ni0.5Zn0.5Fe2O4 nanofibres with a pure cubic spinel structure were obtained subsequently by calcination of the composite fibres at high temperatures.This paper investigates the thermal decomposition process,structures and morphologies of the electrospun composite fibres and the calcined Ni0.5Zn0.5Fe2O4 nanofibres at different temperatures by thermogravimetric and differential thermal analysis,x-ray diffraction,Fourier transform infrared spectroscopy and field emission scanning electron microscopy.The magnetic behaviour of the resultant nanofibres was studied by a vibrating sample magnetometer.It is found that the grain sizes of the nanofibres increase significantly and the nanofibre morphology gradually transforms from a porous structure to a necklace-like nanostructure with the increase of calcination temperature.The Ni0.5Zn0.5Fe2O4 nanofibres obtained at 1000 C for 2 h are characterized by a necklace-like morphology and diameters of 100–200 nm.The saturation magnetization of the random Ni0.5Zn0.5Fe2O4 nanofibres increases from 46.5 to 90.2 emu/g when the calcination temperature increases from 450 to 1000 C.The coercivity reaches a maximum value of 11.0 kA/m at a calcination temperature of 600 C.Due to the shape anisotropy,the aligned Ni0.5Zn0.5Fe2O4 nanofibres exhibit an obvious magnetic anisotropy and the ease magnetizing direction is parallel to the nanofibre axis. 相似文献
7.
Zuci Quan 《Applied Surface Science》2010,256(11):3669-3675
Zn0.95−xCo0.05CuxO (ZCCO, where x = 0, 0.005, 0.01 and 0.015) thin films were deposited on Si (1 0 0) substrates by pulsed laser deposition technique. Crystal structures, surface morphologies, chemical compositions, bonding states and chemical valences of the corresponding elements for ZCCO films were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and X-ray photoelectron spectroscopy (XPS). XRD and FESEM results indicate that crystallite sizes of the highly (0 0 2)-oriented ZCCO films slightly decrease with increasing Cu content. When the Cu content increases from 0 to 0.015, Zn 2p3/2, Co 2p, Cu 2p3/2 and O 1s peaks of the ZCCO film shift towards higher or lower binding energy regions, and the reasons for these chemical shifts are investigated by fitting the corresponding XPS narrow-scan spectra. Both in-plane and out-of-plane magnetization-magnetic field hysteresis loops of the ZCCO films reveal that all the films have room temperature ferromagnetisms (RTFMs). The conceivable origin of the RTFM is ascribed to the combined effects of the local structural disorder resulted from (Co2+, Cu2+, Cu1+)-cations which substitute Zn2+ ions in the ZnO matrices, ferromagnetic coupling between coupled dopant atoms caused by Co2+ (3d74s0) and Cu2+ (3d94s0) spin states, and exchange interactions between the unpaired electron spins originating from lattice defects induced by Cu doping in the Zn0.95Co0.05O matrices. 相似文献
8.
采用溶胶凝胶法在玻璃衬底上制备了Fe,Co共掺Zn0.9FexCo0.1-xO(x=0,0.03,0.05,0.07)系列薄膜.通过扫描电镜(SEM)、X射线衍射(XRD)、X射线光电子谱(XPS)和光致发光(PL)谱对薄膜样品的表面形貌、晶体结构、成分和光学性能进行了研究.XRD结果表明所有ZnO薄膜样品都呈六方纤锌矿结构,在样品中没有观察到与Fe和Co相关的团簇,氧化物及其他杂相的衍射峰,表明共掺杂改善了Fe或Co在ZnO的分散性.XPS测试结果揭示样品中Co离子的价态为+2价;Fe离子的价态为+2价和+3价共存,但Fe相对浓度的增大导致Fe3+含量增加.所有样品的室温光致发光谱(PL)均观察到紫外发光峰和蓝光双峰,其中Fe,Co共掺ZnO薄膜的紫外发光峰较本征ZnO出现蓝移,蓝光双峰峰位没有变化,但发光强度有所减弱;而掺杂ZnO薄膜的绿光发光峰几乎消失.最后,结合微结构和成分分析对薄膜样品的发光机理进行了讨论. 相似文献
9.
采用等离子体增强化学汽相沉积技术生长不同氧含量的氢化非晶氧化硅薄膜(a-SiOx sub>∶H),离子注入铒及退火后在室温观察到很强的光致发光.当材料中氧硅含量比约为1和 1.76时,分别对应77K和室温测量时最强的1.54μm光致发光.从15到250K的变温实验显示 出三个不同的强度与温度变化关系,表明氢化非晶氧化硅中铒离子的能量激发和发光是一个 复杂的过程.提出氢化非晶氧化硅薄膜中发光铒离子来自于富氧区,并对实验现象进行了解 释.氢化非晶氧化硅中铒发光的温度淬灭效应很弱.从15到250K,光致发光强度减弱约1/2.
关键词:
铒
光致发光
氧含量 相似文献
10.
L. BalakrishnanS. Gowrishankar J. ElanchezhiyanN. Gopalakrishnan 《Physica B: Condensed Matter》2011,406(23):4447-4452
We report the influence of Al concentration on electrical, structural, optical and morphological properties of Al-As codoped p-ZnO thin films using RF magnetron sputtering. Al-As codoped p-ZnO films with different Al concentrations were fabricated using As back diffusion from the GaAs substrate and sputtering Al2O3 mixed ZnO targets (1, 2 and 4 at%). The grown films were investigated by Hall effect measurement, X-ray diffraction (XRD), electron probe microanalysis (EPMA), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and atomic force microscopy (AFM) to study the electrical, structural, optical and morphological properties of the films. From the XRD, it was observed that both full-width at half-maximum (FWHM) and c-axis lattice constant have similar trends with respect to Al concentration. Hall measurements showed that the hole concentration increases as the Al concentration increases from 1015 to 1020 cm−3. The increase in hole concentration upon codoping was supported by the red shift in the near-band-edge (NBE) emission observed from room temperature PL spectra. The proposed p-type mechanism due to AsZn-2VZn complex was confirmed by low temperature PL and XPS analysis. The low FWHM, resistivity and peak-to-valley roughness observed by XRD, Hall measurement and AFM, respectively, suggest that 1 at% Al-doped ZnO:As film is the best codoped film. 相似文献
11.
S.Y. Yang B.Y. Man M. LiuC.S. Chen X.G. GaoC.C. Wang B. Hu 《Applied Surface Science》2011,257(9):3856-3860
Zn1−xCoxO thin films with c-axis preferred orientation were deposited on sapphire (0 0 0 1) by pulsed laser deposition (PLD) technique at different substrate temperatures in an oxygen-deficient ambient. The effect of substrate temperature on the microstructure, morphology and the optical properties of the Zn1−xCoxO thin films was studied by means of X-ray diffraction (XRD), atomic force microscopy (AFM), UV-visible-NIR spectrophotometer, fluorescence spectrophotometer. The results showed that the crystallization of the films was promoted as substrate temperature rose. The structure of the samples was not distorted by the Co incorporating into ZnO lattice. The surface roughness of all samples decreased as substrate temperature increased. The Co concentration in the film was higher than in the target. Emission peak near band edge emission of ZnO from the PL spectra of the all samples was quenched because the dopant complexes acted as non-radiative centers. While three emission bands located at 409 nm (3.03 eV), 496 nm (2.5 eV) and 513 nm (2.4 eV) were, respectively, observed from the PL spectra of the four samples. The three emission bands were in relation to Zn interstitials, Zn vacancies and the complex of VO and Zni (VOZni). The quantity of the Zn interstitials maintained invariable basically, while the quantity of the VOZni slightly decreased as substrate temperature increased. 相似文献
12.
采用脉冲激光沉积(PLD)方法在单晶Si(100)衬底上沿c轴方向生长单晶Zn1-xMgxO薄膜,通过X射线衍射(XRD)、原子力显微镜(AFM)、扫描电镜(SEM)和荧光光谱(PL)研究了膜厚、Mg含量、退火温度及氧气氛等制备工艺对Zn1-xMgxO薄膜的结构、形貌和光学性质的影响.实验结果表明,Mg含量x≤0.15时, Zn关键词:
1-xMgxO薄膜')" href="#">Zn1-xMgxO薄膜
制备工艺
结构
光学性质 相似文献
13.
Chia-Lung Tsai Chia-Jyi Liu Yu-Tai Shih Chao-Shien Huang Ya-Hui Chen 《Applied Surface Science》2009,255(20):8643-8647
Co0.2AlxZn0.8−xO films prepared with different molar ratio of aluminum nitrate to zinc acetate were deposited on substrates by the sol-gel technique. X-ray diffraction, photoluminescence and ferromagnetism measurements were used to characterize the Co0.2AlxZn0.8−xO diluted magnetic semiconductors. The authors found that the intensity of the acceptor-related photoluminescence increased with increasing aluminum concentration and an increase in the number of the acceptor-like defects (zinc vacancies especially) in the Co0.2AlxZn0.8−xO film might lead to the enhancement of the magnetic properties. This implies that controls of the aluminum concentration and the number of the acceptor-like defects are important factors to produce strong ferromagnetism Co0.2AlxZn0.8−xO films prepared by the sol-gel method. 相似文献
14.
Zn1−xCoxO films were grown on glass by sol–gel spin coating process. The Zn1−xCoxO thin films with 10 at.% Co were highly c-axis oriented. The electrical resistivity of the films at 10 at.% Co had the lowest value due to the highest c-axis orientation. XPS and AGM analyses indicated that Co metal clusters weren’t formed, and the ferromagnetism was appeared at room temperature. The characteristics of the electrical resistivity and room temperature ferromagnetism of sol–gel derived Zn1−xCoxO films suggest a potential application to dilute magnetic semiconductor devices. 相似文献
15.
Ling Wei 《Applied Surface Science》2009,255(9):4992-4995
Zn1−xCoxO (0 ≤ x ≤ 0.15) thin films grown on Si (1 0 0) substrates were prepared by a sol-gel technique. The effects of Co doped on the structural, optical properties and surface chemical valence states of the Zn1−xCoxO (0 ≤ x ≤ 0.15) films were investigated by X-ray diffraction (XRD), ultraviolet-visible spectrometer and X-ray photoelectron spectroscopy (XPS). XRD results show that the Zn1−xCoxO films retained a hexagonal crystal structure of ZnO with better c-axis preferred orientation compared to the undoped ZnO films. The optical absorption spectra suggest that the optical band-gap of the Zn1−xCoxO thin films varied from 3.26 to 2.79 eV with increasing Co content from x = 0 to x = 0.15. XPS studies show the possible oxidation states of Co in Zn1−xCoxO (0 ≤ x ≤ 0.05), Zn0.90Co0.10O and Zn0.85Co0.15O are CoO, Co3O4 and Co2O3, with an increase of Co content, respectively. 相似文献
16.
Xiaoyong Xu Chunxiang Xu Jun Dai Jing Pan Jingguo Hu 《Journal of Physics and Chemistry of Solids》2012,73(7):858-862
The corresponding evolutions of morphologies, defect-states and the PL properties have been employed to explore the defect-origins of visible emissions and growth mechanisms of microstructured ZnO. ZnO microtube and microrod whiskers were fabricated by non-catalytic vapor-phase transport using ZnO and graphite powders in air. The microstructures of the samples were studied in detail based on scanning electron microscopy (SEM), x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDX), and electron paramagnetic resonance (EPR). The main PL emission bands evolve from blue to green, which corresponds to that the main defect-states change from Zn interstitials (Zni) to O vacancies (VO). The formation of Zni under the high temperature zinc-rich vapor environment is crucial both for the blue emission and for the formation of the microtubes. 相似文献
17.
Bi1.5Zn1.0Nb1.5O7/Ba0.6Sr0.4TiO3/Bi1.5Zn1.0Nb1.5O7 tunable multilayer thin film has been fabricated by pulsed laser ablation and characterized. Phase composition and microstructure of multilayer films were characterized by X-ray diffraction, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The film has very smooth surface with RMS roughness of 1.5-2 nm and grain size of 100-150 nm. Total film thickness has been measure to be 375 nm. The BZN thin films at 300 K, on Pt(1 1 1)/SiO2/Si substrate showed zero-field dielectric constant of 105 and dielectric loss tangent of 0.002 at frequency of 0.1 MHz. Thin films annealed at 700 °C shows the dielectric tunability of 18% with biasing field 500 kV/cm at 0.1 MHz. The multilayer thin film shows nonferroelectric behavior at room temperature. The good physical and electrical properties of multilayer thin films make them promising candidate for tunable microwave device applications. 相似文献
18.
Arun Aravind K. Hasna M. K. Jayaraj Mukesh Kumar Ramesh Chandra 《Applied Physics A: Materials Science & Processing》2014,115(3):843-849
Phase pure Zn1?x Co x O thin films grown by pulsed laser deposition have transmittance greater than 75 % in the visible region. Raman studies confirm the crystalline nature of Zn1?x Co x O thin films. Zn0.95Co0.05O thin films show room temperature ferromagnetism with saturation magnetization of 0.4μ B /Co atom. The possible origin of paramagnetism at higher Co doping concentrations can be attributed to the increased nearest-neighbor antiferromagnetic interactions between Co2+ ions in ZnO matrix. XPS confirms the substitution of Co2+ ions into the ZnO host lattice. 相似文献
19.
Huilian Liu Lianhua Fei Jinghai Yang Xin Jin Xiaoyan Liu Ming Gao 《Solid State Communications》2011,151(24):1864-1868
Zn0.95Cu0.02Cr0.03O powders have been synthesized by the sol-gel method and sintered in argon atmosphere under different temperatures. The structural, optical and magnetic properties of the powders were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and vibrating sample magnetometer (VSM). The XRD results demonstrated that Cr and Cu ions are incorporated into ZnO successfully when annealing temperatures were 600 and 700 °C. But when the samples were annealed at 500 °C, the crystallinity of the samples was not very good. However, when the annealing temperature was increased to 800 °C, the secondary phase of Cu and ZnCr2O4 appeared in the samples. The PL spectra revealed that the position of the ultraviolet (UV) emission peak of the samples showed a blue shift and the green emission peak enhanced significantly with the annealing temperature increasing from 600 to 700 °C. Magnetic measurements indicated that the room temperature ferromagnetism of Zn0.95Cu0.02Cr0.03O was intrinsic in nature. In addition, the saturation magnetization (Ms) increased from 0.0078 to 0.0088 emu/g with the annealing temperature increased from 600 to 700 °C. 相似文献
20.
利用等离子体辅助分子束外延设备(P-MBE)在m面的蓝宝石(m-Al2O3)衬底上制备了ZnO/Zn0.85Mg0.15O多量子阱.反射式高能电子衍射谱(RHEED)图样的原位观察表明,多量子阱结构是以二维模式生长的.从光致发光谱中可以看到ZnO/Zn0.85Mg0.15O多量子阱在室温仍具有明显的量子限域效应.在290 K时阱宽为3 nm的ZnO/Zn0.85
关键词:
等离子体辅助分子束外延
ZnO多量子阱
光致发光 相似文献