射频磁控溅射法制备SnO2:Sb薄膜的结构和光致发光性质研究

采用射频磁控溅射法在玻璃衬底上制备出锑掺杂的氧化锡（SnO2₂:Sb）薄膜.制 备薄膜是具有纯氧化锡四方金红石结构的多晶膜薄，晶粒生长的择优取向为［110］.室温下光致发光测量结果表明，在392nm附近存在强的紫外-紫光发射.研究了不同氧分压对薄膜结构及发光性质的影响，并对SnO2₂:Sb的光致发光机制进行了探索性研究.     

铒、钪膜中离子注入氦的热解析行为

采用热解析法初步研究了铒、钪膜中离子注入氦的热解析行为。研究结果表明:同种元素铒中离子注入氦的热释放峰位相同,但膜的致密性将影响氦的释放量,结构疏松的膜中存在的孔洞是氦的快速释放通道;在相同注入剂量和能量条件下,铒、钪膜中注入氦的热释放峰位不同,这可能与氦在铒、钪膜中的深度分布及膜的致密性有关,利用质子增强背散射法测量出能量为60 keV的4He+在铒、钪膜中的注入深度分别为210,308 nm。     

Fe掺杂对溶胶凝胶法制备的ZnO: Ni薄膜结构及发光特性的影响

采用溶胶凝胶法在玻璃基片上制备了ZnO及Ni, Fe共掺杂的Zn_0.95-xNi_0.05Fe_xO (x=0, 0.005, 0.01, 0.03, 0.05) 薄膜. 通过扫描电镜(SEM) 和X射线衍射(XRD) 研究了薄膜样品的表面形貌和晶体结构. 结果表明所有样品都具有(002) 择优取向, Fe掺杂导致ZnO: Ni薄膜的晶体质量变差, 晶粒尺寸减小, 但适当的Fe掺杂有利于获得致密、 均匀的薄膜. XPS测试结果表明样品中Ni离子的价态为+2价, Fe离子的价态为+2价和+3价.室温光致发光(PL) 测量表明, 所有样品均观察到较强的紫外发光峰, 蓝光双峰和绿光发光峰. ZnO: Ni薄膜的发光强度可以通过Fe掺杂进行有效调节. 进而我们讨论了Ni, Fe共掺杂ZnO样品的发光机理.     

In2O3 透明薄膜晶体管的制备及其电学性能的研究

采用磁控溅射方法在玻璃衬底上生长了In₂O₃晶体薄膜.该薄膜具有(111)晶面择优取向,晶粒尺寸达到33 nm.利用光刻工艺制作了以In₂O₃晶体薄膜为沟道层的底栅式薄膜晶体管.In₂O₃薄膜晶体管具有良好的栅压调制特性,场效应迁移率达到6.3 cm²/(V·s),开关电流比为3×10³,阈值电压为-0.9 V.结果表明,In相似文献   

Ni离子注入多晶ZrO2的表面电性能和结构

对氧化钇(Y₂O₃)部分稳定氧化锆(ZrO₂)样品在室温下进行了Ni离子注入(140kev,5×10¹⁵-2×10¹⁷ios/cm²)和热退火处理.应用电学测量,Rutherford背散射技术(RBS),X射线光电子能谱(XPS)和喇曼光谱方法研究了Ni离子注入多晶ZrO₂的表面电性能,注入层结构及其热退火的影响。     

机械-化学方法在硅(100)表面制备芳香烃重氮盐单层膜

利用机械-化学方法同时实现硅表面的图形化和功能化. 在芳香烃重氮盐(C₆H₅N₂BF₄)中用金刚石刀具刻划单晶硅(100),使单晶硅表面的Si-O键断裂,形成硅的自由基,进而它们与溶液中含有的有机分子共价结合以形成自组装单层膜. 用原子力显微镜对自组装前后的表面形貌进行表征,用飞行时间二次离子质谱和红外光谱对自组装单层膜进行检测和分析,通过确认C₆H₅离子的存在证明自组装单层     

注镧Co-Cr合金表面氧化膜生长规律与微观结构表征

采用热重分析(TGA)方法研究了离子注镧对Co-40Cr合金在1000℃空气中的恒温氧化和循环氧化行为的影响. 用扫描电镜(SEM)和透射电镜(TEM)对表面氧化膜的微观形貌和结构进行了研究. 用二次离子质谱(SIMS)对合金表面元素铬结合能的变化情况以及氧化膜中元素镧的深度分布进行了测试, 并用激光拉曼谱(Raman)对掺杂镧引起的氧化膜内应力改变进行了测量研究.结果表明, 离子注镧后Co-40Cr合金在1000℃空气中的恒温氧化速率显著降低, 表面Cr₂O₃     

离子注入对C60薄膜结构的影响

利用高能离子注入技术系统地研究了不同剂量、不同种类离子注入对C₆₀薄膜结构的影响,并利用Raman光谱对其结构进行分析．结果表明：中等能量的离子注入会影响C₆₀薄膜的结构,使C₆₀分子薄膜产生聚合和非晶碳化现象,但上述现象的出现与注入离子的剂量大小有关,并存在一注量阈值,只有在此阈值之上,C₆₀薄膜结构才发生改变,研究表明这与注入离子同C₆₀分子之间互作用方式有关.     

p型ZnO薄膜的制备及特性

采用射频磁控溅射在Si片上制备ZnO薄膜，通过离子注入对样品进行N掺杂，在不同温度下进行退火并实现了p型转变.用扫描电子显微镜、X射线衍射和Hall测量对薄膜进行了表征，结果表明薄膜具有良好的表面形貌和高度c轴择优取向，退火后p型ZnO薄膜的最高载流子浓度和最低电阻率分别为1.68×10¹⁶cm^-3和41.5Ω·cm.讨论并分析了退火温度和时间对ZnO薄膜p型转变的影响.     

利用聚乙烯亚胺修饰的CaCO3仿生模板合成3D花朵型二氧化硅微球

利用聚乙烯亚胺(PEI)修饰的碳酸钙仿生模板合成了具有3D花朵型形貌的SiO₂微球.通过调整碳酸钙微粒表面不同浓度PEI的吸附量实现SiO₂微球的形貌控制呈现花朵或刀锋的形状. 用XPS和SEM对制备的SiO₂微粒进行表征. 结果表明,不用浓度的PEI修饰可以较好地控制3花朵型DSiO₂微球的形貌.     

Investigation of structural and magnetic properties of Ni, NiFe and NiFe2O4 thin films

Soft magnetic thin films of Ni, NiFe and NiFe₂O₄ were prepared using reactive magnetron sputtering in various deposition conditions. Experimentally observed soft magnetic property was compared and correlated with nanocrystalline structure evolution. Ni and NiFe deposited films are textured with fcc(111) phase preferred orientation. Accordingly, grain size and lattice parameter were calculated from X-ray diffraction (111) peak line width and 2θ peak position. Addition of reactive gas oxygen in deposition process has substantial effect on crystalline structure of film. There is phase transition from the ordered NiFe (111) structure to the NiFe₂O₄ nanocrystalline phase. The resulting film has shown small X-ray diffraction intensity peak corresponding to (311) and (400) orientation, indicating small amount of existing NiFe₂O₄ phase. The mechanism has been discussed to be responsible for nanocrystallization and amorphization of NiFe₂O₄ films. Magnetic measurement (M-H) loop reveal soft magnetic nature of films with magnetic anisotropy. The coercivity (H_c) of films is in accordance with random anisotropy model, where H_c reduced with grain size. The structural transformation was supported by Fourier transforms infrared spectroscopy measurement. The films are highly smooth with surface roughness in the range of ∼0.53-0.93 nm. NiFe₂O₄ films have shown lowest surface roughness with highest electrical resistivity values. The structural, surface, magnetic and infrared spectroscopy results are observed and analyzed.     

Oriented Growth of Nanocrystalline Gamma Ferric Oxide in Electrophoretically Deposited Films

Films of nanocrystalline γ-Fe₂O₃ were deposited on silicon substrates by using the technique of electrophoretic deposition. The precursor powder was nanocrystalline γ-Fe₂O₃, which was synthesized, using DC arc plasma in the oxygen ambient by vapour–vapour interaction in gas phase condensation; at a stabilized arc current of 40 A. This powder was characterized by X-ray diffraction, Transmission Electron Microscopy, Vibrating Sample Magnetometer and Mössbauer Spectroscopy. An increase in directional coercivity was observed in case of films deposited on silicon substrates, which is dramatically significant. Preferred orientation of almost similar sized nanocrystalline magnetic domains in deposited films is evident from the results of X-ray diffraction and Transmission Electron Microscopy results. The preferred alignment of the nanocrystallites seems to be responsible for the significant changes observed in magnetic properties of films.     

Electrochromic and photoluminescence properties of cobalt oxide thin films prepared by spray pyrolysis

Cobalt oxide thin films were prepared by a facile spray pyrolysis technique, using a perfume atomizer with an aqueous solution of hydrated cobalt chloride salt with a molar concentration of 0.025?M as a source of cobalt. The films were deposited onto glass substrates at temperature of 350?°C. The structural, morphological, and electrochromic properties of the obtained films were studied. It was found from X-ray diffraction analysis that the films were polycrystalline in nature with spinel-type cubic structure and preferred orientation along [111] direction. The Scanning Electron Microscopy images revealed a porous structure with the average grain size around 200?nm. The cyclic voltammetry measurements revealed that Cobalt oxide thin film is an anodically coloring electrochromic material with a transmittance variation in the visible range of 31%, and a fast response time (about 2?seconds) and a good cycling stability. These electrochromic performances make cobalt oxide thin film an attractive material for using as an anodic electrochromic material in smart windows devices. The photoluminescence spectra exhibited a strong emission in the visible region confirming the good crystallinity properties of Co₃O₄ thin films.     

Structural study of Mn-doped ZnO films by TEM

The structural study of diluted magnetic semiconductors is important for interpreting the ferromagnetic behavior associated with the materials. In the present work, a series of low concentration Mn-doped ZnO thin films synthesized by pulsed laser deposition was studied by electron microscopy. All films show the wurtzite structure with (001) preferred growth orientation on the Si substrate. Electron diffraction experiments indicate the deterioration of the growth orientation in some areas of the films with increasing Mn concentration, and the existence of a secondary phase, of Mn₂O₃-type, in the films with larger Mn concentrations. High-resolution electron microscopy images confirm the existence of the secondary phase in the grain boundary of the Mn-doped ZnO phase. The magnetic properties of Mn-doped ZnO are discussed in relation to the structures of the films.     

Microstructural, optical and spectroscopic studies of laser ablated nanostructured tantalum oxide thin films

Thin films of tantalum oxide (Ta₂O₅) have been prepared by pulsed laser deposition technique at different substrate temperatures (300-973 K) under vacuum and under oxygen background (pO₂ = 2 × 10⁻³ mbar) conditions. The films are annealed at a temperature of 1173 K. The as-deposited films are amorphous irrespective of the substrate temperature. XRD patterns show that on annealing, the films get crystallized in orthorhombic phase of tantalum pentoxide (β-Ta₂O₅). The annealed films deposited at substrate temperatures 300 K and 673 K have a preferred orientation along (0 0 1) plane, whereas the films deposited at substrate temperatures above 673 K show a preferred orientation along (2 0 0) crystal plane. The deposited films are characterized using techniques such as grazing incidence X-ray diffraction (GIXRD), atomic force microscopy (AFM), micro-Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and UV-visible spectroscopy. FTIR and micro-Raman measurements confirm the presence of Ta-O, Ta-O-Ta and O-Ta-O bands in the films. Grain size calculations from X-ray diffraction and AFM show a decrease with increase in substrate temperature. The variation of transmittance and band gap with film growth parameters are also discussed.     

Epitaxial growth of highly transparent and conducting Sc-doped ZnO films on c-plane sapphire by sol–gel process without buffer

Highly transparent and conductive scandium doped zinc oxide (ZnO:Sc) films were deposited on c-plane sapphire substrates by sol–gel technique using zinc acetate dihydrate [Zn(CH₃COO)₂·2H₂O] as precursor, 2-methoxyethanol as solvent and monoethanolamine as a stabilizer. The doping with scandium is achieved by adding 0.5 wt% of scandium nitrate hexahydrate [(ScNO₃·6H₂O)] in the solution. The influence of annealing temperature (300–550 °C) on the structural, optical and electrical properties was investigated. X-ray Diffraction study revealed that highly c-axis oriented films with full-width half maximum of 0.16° are obtained at an annealing temperature of 400 °C. The surface morphology of the films was judged by SEM and AFM images which indicated formation of grains. The average transmittance was found to be above 92% in the visible region. ZnO:Sc film, annealed at 400 °C exhibited minimum resistivity of 1.91 × 10⁻⁴ Ω cm. Room-temperature photoluminescence measurements of the ZnO:Sc films annealed at 400 °C showed ultraviolet peak at 3.31eV with a FWHM of 11.2 meV, which are comparable to those found in high-quality ZnO films. Reflection high-energy electron diffraction pattern confirmed the epitaxial nature of the films even without introducing any buffer layer.     

厚度对未掺杂ZnO薄膜光谱性能的影响

X射线衍射光谱、拉曼光谱和紫外可见透射光谱技术是薄膜材料检测的重要技术手段。通过对薄膜材料光谱性能的分析,可以获得薄膜材料的物相、晶体结构和透光性能等信息。为了解厚度对未掺杂ZnO薄膜的X射线衍射光谱、拉曼光谱和紫外可见透射光谱性能的影响,利用溶胶-凝胶法在石英衬底上旋涂制备了不同厚度的未掺杂ZnO薄膜样品,并对薄膜样品进行了X射线衍射光谱、拉曼光谱和紫外可见透射光谱的检测。首先,通过X射线衍射光谱检测发现,薄膜样品呈现出（002）晶面的衍射峰,ZnO薄膜为六角纤锌矿结构,均沿着C轴择优取向生长,且随着薄膜厚度的增加,衍射峰明显增强,ZnO薄膜的晶粒尺寸随着膜厚的增加而长大。利用扫描电子显微镜对薄膜样品的表面形貌分析显示,薄膜表面致密均匀,具有纳米晶体的结构,其晶粒具有明显的六角形状。通过拉曼光谱检测发现,薄膜样品均出现了437 cm-1的拉曼峰,这是ZnO纤锌矿结构的特征峰,且随着薄膜厚度的增加,其特征拉曼峰强度也增加,进一步说明了随着ZnO薄膜厚度的增加,ZnO薄膜晶化得到了加强。最后,通过紫外可见透射光谱测试发现,随着膜厚的增加,薄膜的吸收边发生一定红移,薄膜样品在可见光区域内的透过率随着膜厚度增加而略有降低,但平均透过率都超过90%。通过对薄膜样品的紫外-可见透射光谱进一步分析,估算了薄膜样品的折射率,定量计算了薄膜样品的光学禁带宽度,计算结果表明：厚度的改变对薄膜样品的折射率影响不大,但其禁带宽度随着薄膜厚度的增加而变窄,且均大于未掺杂ZnO禁带宽度的理论值3.37 eV。进一步分析表明,ZnO薄膜厚度的变化与ZnO晶粒尺寸的变化呈正相关,本质上,吸收边或光学禁带宽度的变化是由于ZnO晶粒尺寸变化引起的。     

Characteristics of filtered vacuum arc deposited ZnO-SnO2 thin films on room temperature substrates

ZnO, SnO₂ and zinc stannate thin films were deposited using filtered vacuum arc deposition (FVAD) system on commercial microscope glass and UV fused silica substrates (UVFS) at room temperature (RT). The structural and morphological analyses were performed using X-ray diffraction (XRD) and Atomic Force Microscopy (AFM), respectively. XRD patterns of ZnO films deposited at RT had strongly c-axis orientation, whereas SnO₂ and zinc stannate films had amorphous structure as they did not have any defined patterns. Average crystalline size and surface grain size of ZnO films were ∼16 nm, as determined from diffraction line broadening and AFM images, respectively. Optical constants in the 250-1100 nm wavelength range were determined by variable angle spectroscopic ellipsometry and transmission measurements. The transmission of the deposited films in the VIS was 80-90%, affected by interference. The refractive indices and the extinction coefficients of deposited ZnO, SnO₂ and zinc stannate films were in the range 1.87-2.15 and 0.02-0.04, depending on wavelengths and deposition parameters. The optical band gap (E_g) was determined by the dependence of the absorption coefficient on the photon energy at short wavelengths. Its values for ZnO, SnO₂ and zinc stannate were in the range 3.25-3.30 eV, 3.60-3.98 eV and 3.43-3.52 eV, respectively, depending on the deposition pressure.     

Mechanical properties of sol-gel derived lead zirconate titanate thin films by nanoindentation

Lead zirconate titanate (PZT) thin films are deposited on platinized silicon substrate by sol-gel process. The crystal structure and surface morphology of PZT thin films are characterized by X-ray diffraction and atomic force microscopy. Depth-sensing nanoindentation system is used to measure mechanical characteristics of PZT thin films. X-ray diffraction analyses confirm the single-phase perovskite structures of all PZT thin films. Nanoindentation measurements reveal that the indentation modulus and hardness of PZT thin films are related with the grain size and crystalline orientation. The increases of the indentation modulus and hardness with grain size are observed, indicating the reverse Hall-Petch effect. Furthermore, the indentation modulus of (1 1 1)-oriented PZT thin film is higher than those of (1 0 0)- and random-oriented films. The consistency between experimental data and numerical results of the effective indentation moduli for fiber-textured PZT thin films using Voigt-Reuss-Hill model is obtained.