VTD法制备不同基底倾角的硒化锑薄膜及太阳电池

硒化锑(Sb₂Se₃)具有较高丰度及良好的光电特性,是当前热门太阳电池材料之一。目前,在Sb₂Se₃的多种制备方法中,气相转移沉积法(VTD)因工艺简单且可大面积制备而备受关注。采用VTD法制备Sb₂Se₃薄膜的影响因素有多种,如腔体气压、反应温度、蒸发源与衬底的位置以及生长角度等。本文利用VTD法以不同的生长角度(30°、45°、60°、90°)制备了Sb₂Se₃薄膜,对其进行XRD、Raman、SEM、近红外-紫外反射表征。结果表明不同生长角度对薄膜的结构以及光学特性具有明显的影响。晶粒尺寸随着生长角度的增加而先增大后减小,同时薄膜的形貌由棒状生长转变为片状生长,在基底倾角为90°时,薄膜变得最为致密。近红外-紫外反射光谱表明倾角60°的样品在波长小于1 100 nm的范围具有最低的反射率,在该角度下制备的FTO/CdS/Sb₂Se₃/C器件获得了2.38%的转换效率。     

制备方法对钙钛矿薄膜结构及形貌的影响

采用液相连续沉积法制备了有机/无机杂化钙钛矿（CH₃NH₃PbI₃,MAPbI₃）光吸收层,并研究了不同薄膜形貌、晶体结构和光吸收能力对钙钛矿太阳能电池性能的影响。结果表明：制备工艺对吸光层形貌和器件光电性能产生很大的影响。相对于分步浸渍法,分步旋涂法（分步旋涂无机相碘化铅PbI₂和有机相甲胺碘CH₃NH₃I前驱液）和气体辅助修复法（新制初始MAPbI₃薄膜在室温下置于甲胺气氛中）能有效改善薄膜形貌和平整度,获得覆盖完全的均匀钙钛矿吸光层。同时,进一步分析了初始MAPbI₃膜的形貌对气体修复法制备全覆盖平整钙钛矿薄膜的影响,发现初始钙钛矿膜的形貌对最终修复后的膜层形貌没有影响,这可能是因为不同初始MAPbI₃膜经甲胺气体处理后均形成一种"甲胺铅化碘-甲胺"（MAPbI₃·MA）的液态中间相,再经退火处理后均获得平整、致密的钙钛矿膜层,极大地提高了MAPbI₃的结晶度和薄膜均匀性,从而提高活性层的吸光率、光电流和电池效率。     

NbO x 掺杂对Pt/TiO2催化燃烧氯乙烯的促进作用

通过制备Pt/Nb _x /TiO₂研究了NbO _x 在催化燃烧氯乙烯中的作用;采用XRD、XPS、H₂-TPR、NH₃-TPD与Py-FT-IR表征了NbO _x 对于催化剂组织结构、氧化还原以及酸碱性的影响。负载NbO _x 可促进Pt/TiO₂反应性能的提高,当Nb/Ti摩尔比为0.09时,即Pt/Nb_0.09/TiO₂可在246℃实现90%氯乙烯的转化;与Pt/TiO₂相比,达到相同转化率的温度向低温偏移69℃。NbO _x 也影响了催化燃烧过程中的含氯副产物的总浓度和分布。催化剂表征结果发现NbO _x 的引入可进一步增加Pt与载体（TiO₂）之间的相互作用,提高催化剂的表面活性氧物种的浓度,进而促进了催化剂氧化还原性能的提高。催化剂表面的总酸量随着NbO _x 含量的增加而降低,尤其是表面Lewis酸量。因此,催化剂表面的酸量和酸分布不是决定反应性能的唯一因素,而低温的氧化还原性更有利于催化剂性能的提高。     

NbO x 掺杂对Pt/TiO2催化燃烧氯乙烯的促进作用

通过制备Pt/Nb _x /TiO₂研究了NbO _x 在催化燃烧氯乙烯中的作用;采用XRD、XPS、H₂-TPR、NH₃-TPD与Py-FT-IR表征了NbO _x 对于催化剂组织结构、氧化还原以及酸碱性的影响。负载NbO _x 可促进Pt/TiO₂反应性能的提高,当Nb/Ti摩尔比为0.09时,即Pt/Nb_0.09/TiO₂可在246℃实现90%氯乙烯的转化;与Pt/TiO₂相比,达到相同转化率的温度向低温偏移69℃。NbO _x 也影响了催化燃烧过程中的含氯副产物的总浓度和分布。催化剂表征结果发现NbO _x 的引入可进一步增加Pt与载体（TiO₂）之间的相互作用,提高催化剂的表面活性氧物种的浓度,进而促进了催化剂氧化还原性能的提高。催化剂表面的总酸量随着NbO _x 含量的增加而降低,尤其是表面Lewis酸量。因此,催化剂表面的酸量和酸分布不是决定反应性能的唯一因素,而低温的氧化还原性更有利于催化剂性能的提高。     

化学浴沉积硫化铅薄膜及其晶体结构

采用化学浴沉积法(CBD)在玻璃衬底上制备了PbS薄膜,探究了沉积时间(20～100 min)对其厚度、微观形貌、晶体结构和禁带宽度的影响.结果表明,化学浴沉积所得的PbS薄膜均匀、致密,呈镜面光亮的黑色.随着沉积时间的延长,PbS薄膜厚度先快速后缓慢增大,微观形貌逐渐由片状结构转变为立方体结构,择优生长取向从(200)转变为(220),禁带宽度先减小后增大.沉积60 min所得PbS薄膜的厚度约为853 nm,以(220)晶面为生长取向,禁带宽度为0.205 eV,光学性能最佳.     

若干硫系玻璃黏度变化速率的结构起源探索

用熔融淬冷法制备Ge₃₃As₁₂Se₅₅、Ge₂₂As₂₀Se₅₈、Ge₁₀As₄₀Se₅₀、As₄₀Se₆₀、Se硫系玻璃,采用流变仪测试样品黏弹状态的黏度,计算各样品黏度的Vogel-Fulcher-Tammann 方程和黏度变化速率(即料性)。结合拉曼光谱,根据玻璃微观结构对料性的影响规律进行系统分析。发现随着Ge_xAs_ySe_100-x-y硫系玻璃中Ge、As含量的增加,玻璃黏度随温度的变化速率先降低再升高,料性先变长后变短。在平均配位数=2~2.6时,随着平均配位数的增大,组成玻璃的原子之间的平均键能和网络结构稳定性逐渐变大,黏度变化速率降低,料性变长;在=2.6~2.78时,随着网络结构中As-As/Ge-Ge缺陷键的出现,玻璃网络结构的稳定性降低,玻璃黏度的变化速率加快,料性变短。     

氨分解制氢棒状La x Ce1-x O y 负载Ru催化剂

氨分解得到的H₂不含CO _x 、SO _x 、NO _x 等有害物质,是其他所有含碳资源为原料制氢所不能比拟的。本文采用无模板水热法制备了一系列棒状载体,并采用沉积沉淀法制备了Ru/La _x Ce_1-x O _y 催化剂,考察了制备方法、催化剂组成对性能的影响,并通过扫描电镜（SEM）、X射线衍射（XRD）、BET、H₂-程序升温还原（TPR）和CO₂-程序升温脱附（TPD）进行了表征。结果表明,La₂O₃掺杂量为40%的Ru/La_0.4Ce_0.6O_1.8催化剂在常压、7800h^-1、450℃下氨分解转化率为98%。该催化剂活性高归因于部分还原的CeO_2-x 对Ru的供电子性能和Ru/La_0.4Ce_0.6O_1.8催化剂表面的强碱性增加了对Ru活性位的给电子能力。同时考察了K₂O含量的影响,最优的催化剂为Ru-2%K/La_0.4Ce_0.6O_1.8,在400℃、7800h^-1氨气转化率可以达到93%。结果表明Ru-2%K/La_0.4Ce_0.6O_1.8可以作为一种新型高效氨分解催化剂,为工业化应用提供了可能,具有良好的发展前景。     

脱硝协同汞氧化聚苯硫醚四元催化滤料制备方法及理化特性

采用原位氧化法（ISM）、浸渍煅烧法（ICM）和涂覆法（CM）制备聚苯硫醚（PPS）双效催化滤料,在模拟烟气固定床系统中考察了滤料低温NO_x催化协同Hg⁰氧化性能,深入分析了原位氧化滤料表面形貌、元素分布、晶态结构和Hg及NO_x赋存形态。结果表明：在相同条件下,3种制备方法对应滤料催化活性大小顺序为Mn-Ce-Fe-Co-O_x/PPS@ISM＞Mn-Ce-Fe-Co-O_x/PPS@ICM＞Mn-Ce-Fe-Co-O_x/PPS@CM。ISM对应PPS单层饱和负载量约为0.9,活性反应温度窗口为110~210℃,其中170℃时Mn-Ce-Fe-Co-O_x/PPS@ISM的非均相NO氧化、NO_x还原和Hg⁰氧化效率最高分别达到8.6%、84.6%和93.2%。程序升温脱附实验结果表明：(0.9)Mn-Ce-Fe-Co-O_x/PPS@ ISM表面NO_x吸附活性位点中弱碱位数量占优,而中碱位化学吸附NO主要以NO_y（y=2或3）结构存在,歧化态NO₂次之。同时,Hg与NO在氧气条件下以非均相反应途径转化为HgO和Hg(NO₃)₂/Hg₂(NO₃)₂。表征结果表明：ISM制备的MnO_x、CeO_x、CoO_x和Fe₂O₃复合氧化物呈弱晶相、高度分散团絮状结构赋存于PPS@ISM纤维。     

低温等离子体协同Mn基催化剂降解氯苯研究

以氯代挥发性有机物（CVOCs）中的典型代表氯苯为研究对象,分别采用硝酸锰（MN）和乙酸锰（MA）为前体,通过浸渍法制备Mn基催化剂,考察了低温等离子体协同Mn基催化剂降解氯苯性能以及抑制反应副产物臭氧生成的影响。研究发现对于不同反应系统,提升电压可以提高氯苯降解效率;催化剂引入能够大幅度提高氯苯降解性能,与MnO _x （MN）/γ-Al₂O₃相比,MnO _x （MA）/γ-Al₂O₃引入对氯苯降解效果更好,对臭氧生成的抑制性能更高。利用N₂吸附-脱附、扫描电镜（SEM）、X射线衍射（XRD）、傅里叶红外光谱（FT-IR）和X射线光电子能谱（XPS）等手段对反应前后催化剂进行表征分析,发现放电并未对催化剂的孔径及晶相结构产生影响;通过无机氯选择性和尾气质谱结果分析氯苯降解过程中氯元素变化;与MnO _x （MN）/γ-Al₂O₃催化剂相比,MnO _x （MA）/γ-Al₂O₃催化剂的比表面积相对较大,活性组分分散性更高、更均匀,从而导致反应系统内更多的臭氧在催化剂表面分解为活性氧原子,提高了氯苯的降解性能并抑制了反应系统内臭氧的生成。     

离子对(Nb5+-Cr3+)掺杂对0.93Bi0.5Na0.5TiO3-0.07BaTiO3陶瓷微观结构和电学性能的影响

采用固相烧结法制备(Bi_0.5Na_0.5)_0.93Ba_0.07Ti_1-x(Nb_0.5Cr_0.5)_xO₃(摩尔分数x=0%、0.5%、1%、2%、2.5%、5%)(简称BNBT-xNC)无铅压电陶瓷,研究离子对(Nb⁵⁺-Cr³⁺)对0.93Bi_0.5Na_0.5TiO₃-0.07BaTiO₃(简称BNT-7BT)陶瓷微观结构、介电、铁电和应变性能的影响。结果表明,所有组分为伪立方相。随着离子对(Nb⁵⁺-Cr³⁺)含量增加,BNBT-xNC陶瓷的铁电弛豫特性明显改变,在较低掺杂浓度下(0%≤x≤1%)为非遍历弛豫态,随含量增加(1%≤x≤2%),出现非遍历-遍历弛豫态共存,最后转变为遍历弛豫态(2.5%≤x≤5%);陶瓷从铁电态向弛豫态转变,应变性能先增加后降低,最大应变S_max和逆压电常数d^*₃₃在x=2%时达到最大,分别为0.22%和431 pm/V。     

ELECTROLESS PLATING OF GLASS AND SILICON SUBSTRATES THROUGH SURFACE PRETREATMENTS INVOLVING PLASMA-POLYMERIZATION AND GRAFTING PROCESSES

Electroless plating of nickel (or copper) was carried out on glass (or silicon) substrates that were previously surface modified by using plasma-polymerization and grafting processes, and then activated by immersion in a simple acidic PdCl₂ solution. Three pretreatments based on the deposition of plasma-polymerized thin films (PACVD process) on O₂ plasma-cleaned substrates were investigated. They include film deposition of (1) amorphous hydrogenated carbon (a-C:H) grown from CH₄, whose surface is subsequently plasma-functionalized in NH₃ or N₂; (2) amorphous hydrogenated carbon nitride (a-CN_x:H) grown from CH₄/NH₃ or CH₄/N₂ mixtures; and (3) amorphous hydrogenated carbon nitride grown from volatile organic precursors (allylamine, acetonitrile).

In the three cases, X-ray photoelectron spectroscopy (XPS) results show that chemisorption of the catalyst occurs on the nitrogen-containing functionalities created by plasma polymerization and grafting and thus that the electroless deposition is possible. Differences were observed depending on the nature and thickness of the plasma-polymerized thin films, as well as on the nature and concentration of the nitrogen-containing functionalities present or grafted at the surface. Practical adhesion of Ni films was investigated using a Scotch® tape test. Ni films up to 3 or 4 μm in thickness were shown to pass this test successfully, i.e., without causing any metal detachment.     

Electrophoretic Deposition and Characterization of Micrometer-Scale BaTiO3 Based X7R Dielectric Thick Films

Uniform and relatively dense BaTiO₃ thick films of 1–5 μm were prepared by an electrophoretic deposition process using submicrometer BaTiO₃ powders (mean particle size: ∼0.2 μm). Two different BaTiO₃ powders and solvent media were used to investigate the film quality and thickness control. The surface charge mechanism of BaTiO₃ particles was explained according to the observed results. The microstructures were examined by means of SEM. The experimental results show that the thickness could be controlled independently of suspension concentration by keeping a constant applied voltage and a constant current drop in a given suspension. BaTiO₃ thick films have good insulation resistance and dielectric properties such as a dielectric constant and a dissipation factor that are compatible with the data from conventional tape-cast BaTiO₃ thin layers.     

Chemical Solution Deposition of Columnar-Grained Metallic Lanthanum Nitrate Thin Films

Columnar and (100)-oriented LaNiO₃ thin films were prepared on silicon substrates by a chemical solution deposition (CSD) process using a 0.05 M solution. By reducing the individual layer thickness to 10 nm, columnar LaNiO₃ films with a lateral grain size of ∼120 nm were obtained. The success of this approach required restricting the individual layer thickness to a value below the grain size observed for equiaxed films. This change in microstructure resulted in an improvement in conductivity. The columnar LaNiO₃ film with a thickness of 300 nm showed a resistivity of 4.5 × 10⁻⁵Ω·cm, which is lower by one order of magnitude than that of fine-grain equiaxed films that typically result from CSD methods.     

Nanocrystalline Tin Oxide Thin Films via Liquid Flow Deposition

Nanocrystalline films of SnO₂ were deposited by liquid flow deposition (LFD), i.e., by flowing aqueous solutions of SnCl₄·5H₂O and HCl over single-crystalline silicon substrates at 80°C. The substrates were either oxidized and fully hydrolyzed (bare silicon) or oxidized, hydrolyzed, and then coated with siloxy-anchored organic self-assembled monolayers (SAMs). Continuous, adherent films formed on sulfonate- and thioacetate-functionalized SAMs; adherent but sometimes discontinuous films formed on bare silicon and methyl-functionalized SAMs. The films contained equiaxed cassiterite crystals, ∼4–10 nm in size. The film thickness increased linearly with deposition time. The maximum growth rate observed was 85 nm·h⁻¹ on sulfonate SAM, and the maximum film thickness obtained was 1 μm. A new dimensionless parameter, the normalized residence time, τ, was introduced for the purpose of interpreting the influence of solution conditions (i.e., degree of supersaturation, as controlled via pH, and tin concentration) and flow characteristics (flow rate and the configuration of the deposition chamber) on the growth rate in LFD processes. The results were consistent with a particle attachment mechanism for film growth and inconsistent with heterogeneous nucleation on the substrate.     

Oxide Thickness Measurement in the Electron Probe Microanalyzer

An X-ray method for the measurements of the thickness of supported thin films in the microprobe is modified for silica films on silicon nitride and silicon carbide. The intensities of the oxygen Kα line are measured on bulk SiO₂ and on the film. The derivation of the caliboration curve giving the thickness of the film from the ratio of these intensities is outlined. The method has been used for silica films thinner than 1 μm with a lateral resolution of a few micrometers.     

Lead Zirconate Titanate Thin Films by Aerosol Plasma Deposition: Microstructure Analysis

Lead zirconate titanate (Pb(Zr,Ti)O₃, PZT) thin films were grown on silicon 〈100〉 substrate by aerosol plasma deposition (APD) using solid-state-reacted powder containing donor oxide Nb₂O₅ when keeping the substrate at room temperature and 200°C. Crystalline phases of the deposited films have been analyzed via X-ray diffractometry (XRD), and microstructure via scanning and transmission electron microscopy (SEM and TEM). Cross-sectional TEM revealed that the microstructure comprised several layers including the deposited PZT film and the platinum-electrode-and-titanium-buffered layers on SiO₂–Si substrate. The Pt-electrode layer contained (111)_Pt twinned columnar grains with a slight misorientation and forming low-angle grain boundaries among them. The PZT layer contained randomly oriented grains embedded in an amorphous matrix. Some of the PZT grains, oriented with the zone axis Z = [[Twomacr]11]_PZT parallel to Z = [111]_Pt, were grown epitaxially on the Pt layer by sharing the (111)_PZT plane with the (111)_Pt twinned columnar Pt crystals. However, the existence of such an orientation relationship was confined to several nanosize grains at and near the PZT-Pt interface, and no gross film texture has been developed. An amorphous grain boundary phase, generated by pressure-induced amorphisation (PIA) in the solid state, was identified by high-resolution imaging. Its presence is taken to account for the densification of the PZT thin films via a sintering mechanism involving an amorphous phase on deposition at 25° and 200°C.     

The effect of ammonia/dimethylamine ratio in deposition of hydrogenated CNx films by PE-HF-CVD

We have investigated the influence of ammonia (NH₃) and dimethylamine ((CH₃)₂NH or DA) precursors on the deposition of carbon nitride films in a plasma enhanced-hot filament-chemical vapor deposition process. We found that using C and N directly bonded into precursor, as in DA, notably enhanced the N incorporation and film compactness, as compared to CH₄ precursor or CH₄/NH₃ mixtures. The optical properties of films prepared with DA were investigated by IR and Raman spectroscopy, while the film hardness was investigated by nanoindentation. We found that introducing small amounts of ammonia (NH₃/DA=0.2) during deposition improves film density and N incorporation, but a further increase of ammonia content (0.23/DA<1) is deleterious for films properties. In such cases, the etching effect of NH₃ during deposition prevails over N incorporation in the films.     

Tin oxide thin films deposited by ultrasonic spray pyrolysis

This study investigated microstructure of SnO₂ thin films deposited by ultrasonic spray pyrolysis technique using 0.2 M of SnCl₄·5H₂O in absolute ethanol as a precursor. The deposition temperature (350–450 °C) and time (20–90 min) were varied. The influence of film-deposition conditions on grain size and orientation were discussed. The deposited SnO₂ films were textured polycrystalline films. The preferred orientation of SnO₂ films were quantitatively evaluated by texture coefficient (TC). The mean grain size and film thickness determined by SEM could be controlled over a range of 50–325 nm and 80–2690 nm, respectively.     

Characterization of Photoluminescent (Y1–xEux)2O3 Thin Films Prepared by Metallorganic Chemical Vapor Deposition

The purpose of this study was to identify and correlate the microstructural and luminescence properties of europium-doped Y₂O₃ (Y_{1– x} Eu _x )₂O₃ thin films deposited by metallorganic chemical vapor deposition (MOCVD), as a function of deposition time and temperature. The influence of deposition parameters on the crystallite size and microstructural morphology were examined, as well as the influence of these parameters on the photoluminescence emission spectra. (Y_{1– x} Eu _x )₂O₃ thin films were deposited onto (111) silicon and (001) sapphire substrates by MOCVD. The films were grown by reacting yttrium and europium tris(2,2,6,6-tetramethyl–3,5-heptanedionate) precursors with an oxygen atmosphere at low pressures (5 torr (1.7 × 10³ Pa)) and low substrate temperatures (500°–700°C). The films deposited at 500°C were smooth and composed of nanocrystalline regions of cubic Y₂O₃, grown in a textured [100] or [110] orientation to the substrate surface. Films deposited at 600°C developed, with increasing deposition time, from a flat, nanocrystalline morphology into a platelike growth morphology with [111] orientation. Monoclinic (Y_{1– x} Eu _x )₂O₃ was observed in the photoluminescence emission spectra for all deposition temperatures. The increase in photoluminescence emission intensity with increasing postdeposition annealing temperature was attributed to the surface/grain boundary area-reduction effect.     

Low-Temperature Metal-Organic Chemical Vapor Deposition of Silicon Nitride

Amorphous silicon nitride films have been deposited on single-crystal silicon from the gas mixture of methylsilazane and ammonia at 873 to 1073 K. The films have been characterized by ellipsometry, Fourier transform infrared spectroscopy, and Auger electron spectroscopy. The Si-C, Si-H, and C-H bonds in methylsilazane can be effectively cleaved and the associated C and H species removed. The structure and composition of the films do not show any apparent dependence on the deposition temperature.