Influence of O2/Ar ratio on the properties of transparent conductive niobium-doped ZnO films

Niobium-doped ZnO transparent conductive films are deposited on glass substrates by radio frequency sputtering at 300℃. The influence of O2/Ar ratio on the structural, electrical and optical properties of the as-deposited films is investigated by X-ray diffraction, Hall measurement and optical transmission spectroscopy. The lowest resistivity of 4.0×10^-4Ω· cm is obtained from the film deposited at the O2/Ar ratio of 1/12. The average optical transmittance of the films is over 90%.     

自持金刚石厚膜上沉积N掺杂ZnO薄膜的生长及电学特性

采用金属有机化合物气相沉积(MOCVD)两步生长法在自持化学气相沉积(CVD)金刚石厚膜的成核面上制备ZnO薄膜, 并研究了薄膜的生长特性和电学特性. 结果表明, 在基片温度为600 ℃时沉积得到的ZnO薄膜表面均匀, 取向较一致, 为c轴取向生长. 其载流子迁移率为3.79 cm²/(V·s).      

Optoelectronic and electrochemical behaviour of γ-CuI thin films prepared by solid iodination process

A simple and efficient solid iodination method has been proposed for the fabrication of p-type γ-CuI thin films.The structural,morphological,optical,electrical and electrochemical properties have been investigated in order to serve as an effective hole-transporting layer in solid-state solar cells.The fabricated films exhibited p-type conductivity with resistivity of 7.0×10~(-2)Ωcm,the hole concentration of ～1.13×10~(19)cm~(-3)and the mobility of 18.34 cm~(-2)V~(-1)s~(-1).The cyclic voltammetry result shows a maximum specific capacitance of 43 mF/cm~2 at a scan rate of 10 mV/s.The cyclic stability and capacitance retention were found to be 99.7%.These findings demonstrate that γ-CuI film can be a potential candidate for multiple applications,such as a hole transporting material for solid-state solar cells and electrochemical supercapacitor.     

I-V andC-V properties of TiO2 thin film by pulsed-laser reactive deposition

TiO-2 thin films have bee deposited on p-Si(111) substrates by pulsed-laser ablation of metallic Ti target in the O-3 ambient. The current-voltage and capacitance-voltage of the Al/TiO-2/Si capacitors are measured. The results show that the dielectric constant of thin film after being annealed at 700℃ is found to be 46, and the border trap density and the interface state density at the TiO-2/p-Si interface are 1.8×10 12 cm -2 and 2×10 12 eV -1·cm -2, respectively. The conduction mechanisms of as-deposited films are also discussed.     

Structural and electrical properties of ZnO films on freestanding thick diamond films

In this paper, ZnO films are deposited on freestanding thick diamond films （FTDF） by plasma-assisted metal organic chemical vapour deposition （MOCVD）. Diethyl zinc （DEZn）, O2 and N2O are applied as precursors and different substrate temperatures are used to achieve high quality ZnO films. The influence of substrate temperature on the properties of ZnO films is systematically investigated by X-ray diffraction （XRD）, Hall measurements and electron probe microanalysis （EPMA）. Experimental results demonstrate that ZnO films deposited at 600℃ and 73 Pa display a fine electrical quality and Zn/O atomic ratio plays an important role in the electrical property of ZnO films.     

Styrene polymerization catalyzed by nickel complexes bearing hydroxyindanone-iminate ligands

Activated by methylaluminoxane, mononuclear bis（hydroxyindanone-iminate）nickel complexes Ni[ArN=CC2H3（CH3）C6H2（R）O]2 （Ar = 2,6-i-Pr2C6H3, R=Me（1）, R=CI（2）, and R=H（3）） showed good activity for the styrene polymerization. The effect of many reaction parameters including the AI/Ni ratio, temperature, and reaction time on catalytic activities of catalytic systems and the molecular weights of the obrained polystyrene was ascertained. The highest activity of 1.34×10^5g（PS）·mol^-1（Ni）·h^-1 was obtained under the optimum reaction condition. The ^13C NMR spectra of the polymers revealed that the polymer was isotactic-rich atactic polystyrene. And the coordination mechanism was confirmed by the analyses of the polymer chain end-groups.     

Giant magneto-optical faraday effect of nanometer Fe-In<Subscript>2</Subscript>O<Subscript>3</Subscript> granular films

The giant magneto-optical Faraday effect of nanometer ferromagnetic metal-semiconductor matrix Fe-ln2O3 granular films prepared by the radio frequency sputtering are studied. The result shows that the Faraday rotation angle θF value of the granular film samples with Fe volume fraction x = 35% is of the order of 10^5（°）/cm at room temperature. Temperature dependence of the Faraday rotation angle θF of Fe0.35（In2O3）0.65 granular films shows that θF value below 10 K increases rapidly with the decrease of the temperature, and when T= 4.2 K, θF value is 106（°）/cm. Through the study of the dependence of low field susceptibility on temperature and the hysteresis loops at different temperatures, it has been found that when the temperature decreases to a critical point Tp = 10 K, the transformation of state from ferro-agnetic to spin-glass-like occurs in Fe0.35（In2O3）0.65 granular films. The remarkable increase of the Faraday rotation angle θF value of Fe0.35（In2O3）0.65 granular films below 10 K seems to arise from the sp-d exchange interaction of the granular film samples in the spin-glass-like state.     

Structure and magnetic properties of ZnO:Cr prepared by Cr ion implantation into ZnO crystals

ZnO:Cr layer was prepared by Cr ion implantation into ZnO bulk crystals. The structural, optical, and magnetic properties of the ZnO:Cr layer were studied with X-ray diffraction, photoluminescence, and superconductor quantum interferometer, respectively. The ZnO:Cr layer implanted Cr with a dose of 5 10 16 cm 2 remained wurtzite structure and exhibited near-band-edge photoluminescence at 3.365 eV with full-width at half-maximum of 8.4 meV at 10 K. The magnetic measurement showed that the ferromagnetism changed at room temperature by different Cr concentration. For samples implanted to high doses, remanent magnetization reached 1.805 10 -4 emu/g and coercive field was 244.5 Oe. Hall effect measurement showed a decrease of the resistivity from 251.7 cmto 28.6 cmafter annealing at 800 ℃. The magnetism is interpreted by bound magnetic polarons, which were taken into account of the process that electrons were locally trapped by oxygen vacancies and occupied the orbitals that overlapped with d shell of neighboring Cr ions.     

Influence of post-annealing on the properties of Ta-doped In<Subscript>2</Subscript>O<Subscript>3</Subscript> transparent conductive films

Ta-doped In₂O₃ transparent conductive oxide films were deposited on glass substrates using radio-frequency (RF) sputtering at 300°C. The influence of post-annealing on the structural, morphologic, electrical and optical properties of the films was investigated using X-ray diffraction, field emission scanning electron microscopy, Hall measurements and optical transmission spectroscopy. The obtained films were polycrystalline with a cubic structure and were preferentially oriented in the (222) crystallographic direction. The lowest resistivity, 5.1×10⁻⁴ Ω cm, was obtained in the film annealed at 500°C, which is half of that of the un-annealed film (9.9×10⁻⁴ Ω cm). The average optical transmittance of the films was over 90%. The optical bandgap was found to decrease with increasing annealing temperature.     

Properties of garnet-type Li6La3ZrTaO12 solid electrolyte films fabricated by aerosol deposition method

The garnet-type Li_6La_3ZrTaO_(12)(LLZT) solid electrolyte films were fabricated by aerosol deposition(AD)method.Ball-milled LLZT powder with a cubic garnet structure and a particle size of 1-2 urn was used as raw material and deposited directly on a SUS316L or a glass substrate via impact consolidation.As-deposited LLZT film has a cubic garnet structure but contains Li_2CO_3 and La_2Zr_2O_7 phases.SEM observation revealed that the film consists of LLZT particles fractured into submicron size.The impurity phase formation during AD process was caused by the local heating by the collision between LLZT particles and deposition surface and reaction with CO_2.The Li~+ ion conductivity of LLZT film was estimated to be 0.24 × 10~(-5)S cm~(-1) at room temperature.Electronic conductivity of LLZT film was confirmed to be around 10~(-12) S cm~(-1),indicating the dominant Li~+ ion conduction of LLZT film.     

Rate constants for the reaction of ozone with <Emphasis Type="Italic">n</Emphasis>-butyl, <Emphasis Type="Italic">s</Emphasis>-butyl and <Emphasis Type="Italic">t</Emphasis>-butyl methyl sulfides

The rate constants for the ozone reactions with n-butyl methyl sulfide （n-BMS, CHaCH2CH2CH2SCH3）, sec-butyl methyl sulfide （s-BMS, CH3CH2（CH3）CHSCHa） and tert-butyl methyl sulfide （t-BMS, （CH3）3CSCH3） were measured using our smog chamber under supposedly pseudo-first-order conditions at 30002 K and 760 Torr. The experimental determined rate constants for n-butyl, s-butyl and t-butyl methyl sulfide are （1.23 ± 0.06）×10-19, （5.08 ± 0.19）×10-20 and （2.26 ± 0.14）×10-20 cm3 molecule-1· s-1, respectively. The reactivity-structure relationship of the reactions was discussed and used to illustrate the mechanism of the ozone reaction with thioethers. The results enrich the kinetics data of atmospheric chemistry.     

磁控溅射表面镀膜对Nd2Fe14B稀土永磁体抗腐蚀性能的影响

在Nd₂Fe₁₄B稀土永磁体基体表面,采用磁控溅射（直流+射频）技术制备了Ti/Ni,Ti/Al和Al/Ni等二元合金薄膜和Ti/Al/Ni三元合金薄膜。并通过中性盐雾试验、腐蚀失重计算、电化学腐蚀试验、金相观察等方式,对比研究了不同表面处理对Nd₂Fe₁₄B稀土永磁体基体抗腐蚀性能的影响,并构建了腐蚀模型。研究发现：Ti/Ni,Ti/Al和Al/Ni等二元合金薄膜和Ti/Al/Ni三元合金薄膜均有效地提高了Nd₂Fe₁₄B稀土永磁体基体耐中性盐雾腐蚀和电化学腐蚀的能力;Ti/Al/Ni三元合金薄膜较Ti/Ni,Ti/Al和Al/Ni等二元合金薄膜有更优良的综合耐腐蚀性能,其磁控溅射工艺参数为：Ar流量60 sccm,基片温度常温,Ni,Al,Ti的溅射功率都为250 W,基片转速20 r·min^-1,镀膜均速0.3 nm·s^-1,总计溅射时间1 h。     

Silicon field emission arrays coated with CN<Subscript>x</Subscript> thin films

Arrays of silicon micro-tips were made by etching the p-type (1 0 0) silicon wafers which had SiO₂ masks with alkaline solution. The density of the micro-tips is 2×10⁴ cm⁻². The Scanning Electron Microscope (SEM) photos showed that the tips in these arrays are uniform and orderly. The CN_x thin film, with the thickness of 1.27 μm was deposited on the silicon micro-tip arrays by using the middle frequency magnetron sputtering technology. The SEM photos showed that the films on the tips are smoothly without particles. Keeping the sharpness of the tips will benefit the properties of field emission. The X-ray photoelectron spectrum (XPS) showed that carbon, nitrogen and oxygen are the three major elements in the surfaces of the films. The percents of them are C: 69.5%, N: 12.6% and O: 17.9%. The silicon arrays coated with CN_x thin films had shown a good field emission characterization. The emission current intensity reached 3.2 mA/cm² at 32.8 V/μm, so it can be put into use. The result showed that the silicon arrays coated with CN_x thin films are likely to be good field emission cathode. The preparation and the characterization of the samples were discussed in detail. Foundation item: Supported by the National Natural Science Foundation of China (19975035) Biography: Chen Ming an (1978-), male, Ph. D candidate, research direction: novel functional materials film and ion beam modification of materials.     

A novel Pd/silicalite-1 composite membrane for hydrogen separation

A novel Pd/silicalite-1 composite membrane supported on the macroporous tubular stainless steel substrate was successfully fabricated by electroless plating at 303 K. The structure, morphology and gaseous permeability of the membrane were detected by X-ray diffractiometry （XRD）, scanning electron microscopy （SEM） and single-gas permeation test, respectively. Results confirm the formation of a thin, smooth, and continuous Pd/silicalite-1 composite membrane. The obtained composite membrane shows a high H2 permeance of 1.15×10^-6 mol. m^-2. s^-1. Pa^-1 with moderate H2 selectivity of 250 for H2/N2 at 773 K, at 0.1 MPa pressure drop, suggesting the potential application for H2 separation.     

Pollen flux and vertical dispersion in coniferous and deciduous broadleaved mixed forest in the Changbai Mountains

The pollen flux in coniferous and deciduous broadleaved mixed forest in the Changbai Mountains is presented in one year's experiments. The results indicate that arboreal pollen percentages are more than 65% and pollen flux is higher than 5000 grain·cm-2·a-1,while less than 2% and lower than 1000 grain·cm-2·a-1 for shrubby pollen,and less than 20% and lower than 3000 grain·cm-1·a-1 for herbaceous pollen for most samples at different heights. The pollen assemblages are similar to those in the samples under 8 m height where Pinus and Ouercus are dominant and followed by the few non-local pollen types,and Fraxinus percentages are high with a few non-local pollen types at 16 m to 32 m height as well as non-local pollen clearly increased at 40 m height. Comparisons between pollen assemblages and vegetation composition suggest that similarities are higher for pollen trap samples than for surface moss samples.     

Field Emission Characterization of 1D-Nanostructural ZnO Grown at Low Temperature

Ondeu-ctdio rmse nhsaivoen aaltt rwaicdteed b aan gdr-egaatp d neaaln oosft uartctteunrtialon se bmeiccaounse-of their remarkable physical and chemical properties[1 ,2].Amongthose properties ,the highaspect ratio of these materi-als makes them genuine can…     

Direct electrochemistry and electrocatalysis of horseradish peroxidase in MnO2 nanosheet film

A novel material MnO2 nanosheet has been used as the support matrix for the immobilization of horseradish peroxidase （HRP）. HRP entrapped in MnO2 nanosheet film exhibits facile direct electron transfer with the electron transfer rate constant of 6.86 s^-1. The HRP/MnO2 nanosheet film gives a reversible redox couple with the apparent formal peak potential （E^0＇） of -0.315 V （vs. Ag/AgCl） in pH 6.5 phosphate buffer solution （PBS）. The formal potential E^0＇ of HRP shifts linearly with pH with a slope of -53.75 mV.pH^-1, denoting that an electron transfer accompanies single-proton transportation. The immobilized HRP shows an electrocatslytic activity to the reduction of H2O2. The response time of the biosensor for H2O2 is less than 3 s, and the detection limit is 0.21 μmol · L^-1 based on signal/noise = 3.     

Ohmic contact properties of p-type surface conductive layer on H-terminated diamond films prepared by DC arc jet CVD

With the advantages of high deposition rate and large deposition area, polycrystalline diamond films prepared by direct current (DC) arc jet chemical vapor deposition (CVD) are considered to be one of the most promising materials for high-frequency and high-power electronic devices. In this paper, high-quality self-standing polycrystalline diamond films with the diameter of 100 mm were prepared by DC arc jet CVD, and then, the p-type surface conductive layer with the sheet carrier density of 1011-1013 cm?2 on the H-terminated diamond film was obtained by micro-wave hydrogen plasma treatment for 40 min. Ti/Au and Au films were deposited on the H-terminated diamond surface as the ohmic contact electrode, respectively, afterwards, they were treated by rapid vacuum annealing at different temperatures. The properties of these two types of ohmic contacts were investigated by measuring the specific contact resistance using the transmission line method (TLM). Due to the formation of Ti-related carbide at high temperature, the specific contact resistance of Ti/Au contact gradually decreases to 9.95 × 10?5 Ω·cm2 as the temperature increases to 820℃. However, when the annealing temperature reaches 850℃, the ohmic contact for Ti/Au is degraded significantly due to the strong diffusion and reaction between Ti and Au. As for the as-deposited Au contact, it shows an ohmic contact. After annealing treatment at 550℃, low specific contact resistance was detected for Au contact, which is derived from the enhancement of interdiffusion between Au and diamond films.     

溶胶-凝胶法制备掺铝氧化锌透明导电膜的正交实验研究

采用溶胶-凝胶法制备了掺铝氧化锌(ZnO：Al,ZAO)透明导电膜。对薄膜用X射线衍射(XRD)、扫描电镜(SEM)、四探针仪及紫外 可见分光光度计等分析测试手段进行了表征;通过正交实验探讨了溶胶浓度、铝离子的摩尔掺杂量以及退火温度等因素对其电阻率的影响。结果表明,薄膜电阻率随溶胶浓度、铝离子掺杂量的增加,呈现先减小后增大的趋势,并随退火温度的升高而减小,从而确定了制备ZAO透明导电膜的优化工艺条件为：溶胶浓度0.8mol/L,铝离子的掺杂量1.0%(摩尔分数),退火温度550℃。在优化工艺条件下制得的ZAO透明导电薄膜具有标准的ZnO纤锌矿结构,其电阻率为1.275×10^-3Ω·cm,平均透光率达84%。     

Kinetic studies of the decomposition reaction of adducts of dinuclear Fe(Ⅱ)/O2

Kinetic studies of the decomposition reaction of dinuclear Fe(Ⅱ) adducts [Fe₂(N-Et-HPTB){O₂P(OPh)₂}](Cl- O₄)₂ (1) and [Fe₂(N-Et-HPTB) {O₂P(Ph)₂}] (ClO₄)₂ (2) with O₂ have been carried out at low temperature using UV-vis spectra. The decomposition reaction of Fe(Ⅱ)/O₂ adducts was first-order in the experimental conditions, and the activation parameters were obtained. ?H^¹ = 85.62 kJ·mol^-1, ?S¹ = 19.43 J·mol^-1·K^-1 for compound (1) and ?H^¹ = 97.97 kJ·mol^-1, ?S^¹ = 55.68 J·mol^-1·K^-1 for compound (2). These results are similar to those of dioxygen adducts of other metals complexes and natural enzymes such as methane mono- oxygenase (MMOH).