Preparation of manganese-doped ZnO thin films and their characterization

In this study, pure and manganese-doped zinc oxide (Mn:ZnO) thin films were deposited on quartz substrate following successive ion layer adsorption and reaction (SILAR) technique. The film growth rate was found to increase linearly with number of dipping cycle. Characterization techniques of XRD, SEM with EDX and UV–visible spectra measurement were done to investigate the effect of Mn doping on the structural and optical properties of Mn:ZnO thin films. Structural characterization by X-ray diffraction reveals that polycrystalline nature of the films increases with increasing manganese incorporation. Particle size evaluated using X-ray line broadening analysis shows decreasing trend with increasing manganese impurification. The average particle size for pure ZnO is 29·71 nm and it reduces to 23·76 nm for 5% Mn-doped ZnO. The strong preferred c-axis orientation is lost due to manganese (Mn) doping. The degree of polycrystallinity increases and the average microstrain in the films decreases with increasing Mn incorporation. Incorporation of Mn was confirmed from elemental analysis using EDX. As the Mn doping concentration increases the optical bandgap of the films decreases for the range of Mn doping reported here. The value of fundamental absorption edge is 3·22 eV for pure ZnO and it decreases to 3·06 eV for 5% Mn:ZnO.     

Preparation and characterization of amorphous manganese sulfide thin films by SILAR method

Manganese sulfide thin films were deposited by a simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method using manganese acetate as a manganese and sodium sulfide as sulfide ion sources, respectively. Manganese sulfide films were characterized for their structural, surface morphological and optical properties by means of X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and optical absorption measurement techniques. The as-deposited film on glass substrate was amorphous. The optical band gap of the film was found to be thickness dependent. As thickness increases optical band gap was found to be increase. The water angle contact was found to be 34°, suggesting hydrophilic nature of manganese sulfide thin films. The presence of Mn and S in thin film was confirmed by energy dispersive X-ray analysis.     

脉冲激光沉积ZnO薄膜的制备及其性能研究

本文用脉冲激光沉积(PLD)法在SiO2基片上制备了ZnO薄膜和Zn1-xMnxO薄膜.X射线衍射、原子力显微镜、紫外-可见光分光光度计对ZnO薄膜的测试结果表明:薄膜具有(103)面的择优取向,表面比较平坦;SiO2基片上制备的薄膜在387 nm附近存在明显的吸收边,且薄膜的吸收对基片温度变化不明显.通过对Zn1-xMnxO薄膜的吸收光谱分析得出:Mn离子的掺杂改变了ZnO薄膜的禁带宽度,随着Mn离子掺杂量的增加,薄膜禁带宽度增加;薄膜的光吸收也从直接跃迁过渡为间接跃迁.     

ZnO∶Li压电薄膜制备及其性能研究

ZnO薄膜的高阻特性在压电方面的应用极为重要.采用sol-gel法在Pt/Ti/SiO2/Si衬底上制备了c轴择优取向优良、电阻率高和化学计量比好的掺Li＋（Li/Zn摩尔比分别为0、0.05、0.10、0.15、0.20）ZnO压电薄膜.研究了退火温度、掺杂浓度对ZnO薄膜晶体质量和电学特性的影响.XRD结果表明,ZnO薄膜的c轴择优取向度受退火温度和掺杂浓度的强烈影响;I-V测试表明,掺Li^＋后薄膜的电阻率显著提高,当Li＋掺杂浓度为0.10（Li/Zn摩尔比）、退火温度为600℃时其电阻率达109Ω@cm;XPS分析结果表明,Li＋掺杂对ZnO薄膜中O1s和ZnL3M45M45的结合能以及Zn/O比都有一定的影响,掺杂后化学计量比更好.     

Li-Cu共掺杂ZnO纳米薄膜的溶胶凝胶法制备

采用溶胶-凝胶法,通过调整氯化锂和氯化铜的摩尔比在不同基片上制备了不同Li-Cu共掺杂浓度的ZnO薄膜.利用X射线衍射仪、扫描电子显微镜、透射电子显微镜、紫外可见光分光光度计和伏安特性测试等表征了薄膜的结晶状况、表面形貌及光电特性.结果表明:所得Li-Cu共掺杂ZnO薄膜为六角纤锌矿多晶结构,有CuO杂质相生成.随Li和Cu摩尔比增加,共掺杂ZnO薄膜结晶度增强,晶粒长大,样品表面不平整度增加.CuO颗粒的出现,使得共掺杂ZnO薄膜透射率降低,透光性较差.Li与Cu摩尔比为1∶1时,共掺杂ZnO薄膜的综合导电性最好.     

Effect of multiple dipping of SILAR deposited ZnO thin films by physico-chemical process

Undoped zinc oxide (ZnO) thin films were deposited on microscopic glass substrates by a chemical technique known as ‘Successive Ionic Layer Adsorption and Reaction’. The technique involves multiple dipping of the substrates in an aqueous solution of sodium zincate kept at room temperature and deionized water kept near boiling point. The effect of multiple dipping is one of the important factors that determine the quality of film. Thin films of various thicknesses have been obtained by varying the number of dipping, while all other deposition parameters such as pH of the solution, molarity, reaction temperature, reaction time and annealing temperature were kept constant. The structural, surface morphology and optical properties of the ZnO thin films have been studied using X-ray diffraction (XRD), scanning electron microscope (SEM) and UV–Vis-spectrophotometer. XRD and SEM studies reveal that the grain size increases with the increase in number of dipping of the glass substrate. Optical spectra were recorded using UV–Vis spectrophotometer. The optical band gap of ZnO thin film was found to decrease with increase in the number of dipping.     

Optical and magnetic properties of Mn doped ZnO thin films grown by SILAR method

Polycrystalline Mn doped ZnO (MZO) semiconductor thin films were deposited onto glass substrates employing different number of dipping at room temperature using Successive Ionic Layers by Adsorption Reaction (SILAR) technique. The thin film deposition conditions were optimized by altering the various deposition parameters based on their structure. The structural study was carried out using X-ray diffractometer (XRD). The XRD analysis indicated that there is no change in the structure of ZnO thin films due to Mn doping. The films exhibited hexagonal wurtzite structure. The structural studies on Mn doped samples revealed that the predominant orientation is (002) lattice plane and the position of this orientation shifted toward lower angle during doping. The intensity of photoluminescence (PL) emission of ZnO is found to be augmented for Mn doped samples. The room temperature Raman spectra measurements revealed the presence of additional modes. The Vibrating Sample Magnetometer (VSM) studies show that MZO thin film has ferromagnetic properties.     

Synthesis and characterization of bulk cobalt-doped ZnO and their thin films

(ZnO)_1?x (Co₃O₄) _x≤0.05 thin-film series were deposited in vacuum Ar–O₂ and N₂ environment using the pulsed-laser deposition (PLD) technique. Bulk pellets were prepared by the solid-state reaction technique by mixing ZnO and Co₃O₄ powder and further utilized for deposition of thin films. XRD patterns of pellets exhibit homogeneous ZnCoO phase formation with no other impurity phases. Single-phase (002) oriented ZnCoO thin films were formed without any cobalt segregation. The cobalt core peaks confirmed the existence of +2 valence state of cobalt in thin-film samples, and the binding energy difference between the cores peaks showed the homogeneous doping of cobalt in ZnO matrix. The magnetic ordering was achieved in thin films samples which were deposited in vacuum and N₂ ambience.     

Preparation,characterization and optical properties of nanostructured ZnO thin films

Nanostructured ZnO thin film on a glass slide has been prepared by the spin-coating method together with calcining at 500 °C for 2 h in flowing oxygen atmosphere. The grain size of the ZnO nanoparticles is estimated to be ca. 12 nm as determined by the absorption spectrum and powder X-ray diffraction analysis. The photoluminescent peaks that centered at ca. 379 and 388 nm are assigned to the spontaneous emission and exciton–exciton emission, respectively. The thin film also shows frequency-tripled properties for the output when the laser beam of 1.06 μm is input in convergent beam.     

Preparation and characterization of sol-gel Li and Al codoped ZnO thin films

Li and Al codoped ZnO (LAZO) thin films have been prepared by a sol-gel method and their structural and optical properties have been investigated. The prepared LAZO films had an average transmittance of over 85% in the visible range. The UV absorption edge was red-shifted with Li-doping, whereas it was blue-shifted with Al-doping. A broad yellowish-white emission was observed from the LAZO films annealed above 600 °C. The visible emission was enhanced with increasing annealing temperature and dopant concentration.     

Photoelectrochemical characterization of Bi2Se3 thin films deposited by SILAR technique

Bi₂Se₃ thin films have been deposited by simple and less investigated successive ionic layer adsorption and reaction (SILAR) technique onto fluorine-doped tin oxide (FTO) coated glass substrates at room temperature (27 °C). The X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies indicate that Bi₂Se₃ thin films are nanocrystalline. These films are used for photoelectrochemical (PEC) characterization in cell with configuration as n-Bi₂Se₃/0.1 M polysulfide/C. The studies such as current–voltage characteristics in dark and light, photovoltaic power output, transient photoresponse, and capacitance–voltage have been carried out. The study reveals that fill factor and power conversion efficiency of the cell are low (0.43 and 0.032%, respectively).The flat bond potential is found to be −0.04 V (SCE).     

Preparation of Li and Er codoped ZnO thin films and their photoluminescence

Li-Er codoped ZnO thin films have been prepared on Si(100) substrates by pulsed laser deposition (PLD). Both the as-grown and post-annealed films exhibit good crystalline quality with preferred c-axis orientation. After post-annealing at 850 °C, the photoluminescence (PL) related to intra-4f shell of Er³⁺ can be clearly observed. The Li-Er codoped ZnO film shows higher intensity of PL around 1.54 μm than the Er monodoped ZnO film. The behavior is attributed to the lowering of the symmetry of the crystal field around Er³⁺ ions by introducing Li⁺ into ZnO lattice, which is also confirmed by Raman scattering spectra.     

Preparation of nitrogen-doped YSZ thin films by pulsed laser deposition and their characterization

The pulsed laser deposition technique was applied to deposit nitrogen-doped yttria stabilized zirconia (YSZ) thin films. The working parameters were varied in order to achieve a maximal nitrogen content. The films were characterized by SIMS, XPS, X-ray diffraction and optical spectroscopy. The surface topography was studied by AFM and HRSEM. The influence of the deposition parameters on the film properties is discussed.

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Preparation and characterization of nanostructured ZnO thin films for photoelectrochemical splitting of water

Nanostructured zinc oxide thin films (ZnO) were prepared on conducting glass support (SnO₂: F overlayer) via sol-gel starting from colloidal solution of zinc acetate 2-hydrate in ethanol and 2-methoxy ethanol. Films were obtained by spin coating at 1500 rpm under room conditions (temperature, 28–35°C) and were subsequently sintered in air at three different temperatures (400, 500 and 600°C). The evolution of oxide coatings under thermal treatment was studied by glancing incidence X-ray diffraction and scanning electron microscopy. Average particle size, resistivity and bandgap energy were also determined. Photoelectrochemical properties of thin films and their suitability for splitting of water were investigated. Study suggests that thin films of ZnO, sintered at 600°C are better for photoconversion than the films sintered at 400 or 500°C. Plausible explanations have been provided.     

ZnO∶Al薄膜制备及光电性能研究

利用溶胶-凝胶法在玻璃基板上制备了Al/Zn原子掺杂比例为0～0.25的掺铝氧化锌(ZnO∶Al或AZO)薄膜,随后分别将其在空气,氧气和氮气3种不同气氛中退火处理,研究了薄膜的光学、电学与结构方面的性质.X射线衍射分析表明AZO薄膜是具有c轴择优取向的六方纤锌矿结构多晶体;通过紫外-可见光分光计测定表明该薄膜在可见光范围内具有>80%的高透过率,随着铝掺杂比例的增大光学能隙增大且吸收边向短波方向移动.     

掺氮类金刚石薄膜的制备及其结构表征

采用射频磁控反应溅射法,Ar气为溅射气体,N2气为反应气体,用高纯石墨靶在Si（100）片上制备了掺氮类金刚石薄膜,采用X射线光电子能谱（XPS）、拉曼光谱（Raman）、扫描电子显微镜（SEM）,表征了掺氮类金刚石薄膜的微观结构、表面及截面形貌。Raman光谱结果表明,制备的掺氮类金刚石薄膜中含有特征峰D峰和G峰,分别位于1339．2cm^-1、1554．6cm^-1均向低波数段频移,具有典型的类金刚石结构特征;XPS光谱的C1s和N1s的芯能级证实了薄膜中的碳氮进行了化合,形成了C-N、C=N、C=N,说明薄膜中形成了非晶碳氮结构;同时SEM结果表明实验所制备的薄膜表面均匀、致密、光滑,从截面照片观察,薄膜与衬底结合紧密,薄膜的厚度大约为150nm。     

Optical characterization of ZnO thin films deposited by Sol-gel method

In this paper, ZnO thin film is deposited on Pt/TiO₂/SiO₂/Si substrate using the sol-gel method and the effect of annealing temperature on the structural morphology and optical properties of ZnO thin films is investigated. The ZnO thin films are crystallized by the heat treatment at over 400°C. The ZnO thin film annealed at 600°C exhibits the greatest c-axis orientation and the Full-Width-Half-Maximum (FWHM) of X-ray peak is 0.4360°. A dense ZnO thin film is deposited by the growth of uniform grains with the increase of annealing temperature but when the annealing temperature increases to 700°C, the surface morphology of ZnO thin film becomes worse by the aggregation of ZnO particles. In the results of surface morphology of ZnO thin film using atomic force microscope (AFM), the surface roughness of ZnO thin film annealed at 600°C is smallest, that is, approximately 1.048 nm. For the PL characteristics of ZnO thin film, it is observed that ZnO thin film annealed at 600°C exhibits the greatest UV (ultraviolet) exciton emission at approximately 378 nm, and the smallest visible emission at approximately 510 nm among ZnO thin films annealed at various temperatures. It is deduced that ZnO thin film annealed at 600°C is formed most stoichiometrically, since the visible emission at approximately 510 nm comes from either oxygen vacancies or impurities.     

Preparation and properties of ZnO thin films deposited by sol-gel technique

Zinc oxide (ZnO) thin films were deposited on (100) Si substrates by sol-gel technique. Zinc acetate was used as the precursor material. The effect of different annealing atmospheres and annealing temperatures on composition, structural and optical properties of ZnO thin films was investigated by using Fourier transform infrared spectroscopy, X-ray diffraction, atomic force microscopy and photoluminescence (PL), respectively. At an annealing temperature of 400°C in N₂ for 2 h, dried gel films were propitious to undergo structural relaxation and grow ZnO grains. ZnO thin film annealed at 400°C in N₂ for 2 h exhibited the optimal structure and PL property, and the grain size and the lattice constants of the film were calculated (41.6 nm, a = 3.253 ? and c = 5.210 ?). Moreover, a green emission around 495 nm was observed in the PL spectra owing to the oxygen vacancies located at the surface of ZnO grains. With increasing annealing temperature, both the amount of the grown ZnO and the specific surface area of the grains decrease, which jointly weaken the green emission. Translated from Journal of Lanzhou University (Natural Science), 2006, 42(1): 67–71 [译自: 兰州大学学报 (自然科学版)]     

Mn掺杂ZnO纳米材料的制备与性能研究

采用射频磁控溅射法在Si（100）衬底上沉积过渡族金属Mn掺杂的ZnO薄膜。将5％及7％原子比的MnO，与ZnO粉末充分混合后，加压制成靶材，通过改变溅射过程中的气氛和衬底温度沉积了Zn1-xMnxO薄膜。x射线衍射和场发射扫描电镜的分析表明：掺入≤7％的Mn原子不会改变薄膜的晶体结构，薄膜呈高度（002）晶面择优取向；薄膜表面均匀致密，颗粒尺寸约为30hm；Mn的掺入使薄膜的电学性能明显改善，但氧分压的使用或者Mn含量过大又会使薄膜的电阻率增加。     

Preparation and gas-sensing property of ZnO nanorod-bundle thin films

ZnO nanorod-bundle thin films have been synthesized by a simple self-assembly method with the aid of F₁₂₇ (EO₁₀₆-PO₇₀-EO₁₀₆) triblock copolymer. Their morphologies and crystal structures were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM). SEM results showed that films were composed of a lot of bundles, which comprised nanorods with the diameter of about 10 nm. The possible formation mechanism of ZnO nanorod-bundle structures is proposed. Gas-sensing property of thin films, to alcohol, was also detected. It was also found that the sensitivity, to 100 ppm alcohol, of ZnO nanorod-bundle thin films was higher than that of ZnO nanoparticle thin films. The results showed that the triblock copolymer, served as the surfactants, could effectively control the morphologies and the aspect ratio of nano-ZnO, and then improve its gas-sensing property.