氢稀释比与衬底温度对硅基薄膜相变及其光电性能影响的研究

采用热丝辅助微波电子回旋共振化学气相沉积法(HWAMWECR-CVD),通过改变衬底温度及氢稀释比制备了系列硅基薄膜,研究了衬底温度及氢稀释比对薄膜由非晶相转晶相相变及其光电性能的影响。研究结果表明,当采用低温制备硅基薄膜时,衬底温度和氢稀释比的提高都有利于非晶相向晶相的转变,但提高氢稀释比对相变的影响更为显著;晶化比越高并不代表薄膜光电性能越好,95%氢稀释比条件下制备的微晶硅薄膜具有优良的光电性能。     

脉冲磁控溅射沉积微晶硅薄膜工艺研究

采用脉冲磁控溅射法制备氢化微晶硅薄膜,利用X射线衍射、拉曼光谱、扫描电子显微镜和四探针测试仪对薄膜结构和电学性能进行表征和测试,研究了衬底温度、氢气稀释浓度和溅射功率对硅薄膜结构和性能的影响。结果表明:在一定范围内,通过控制合适的衬底温度、增大氢气稀释浓度及提高溅射功率,可以制备高质量的微晶硅薄膜。在衬底温度为400℃、氢气稀释浓度为90%及溅射功率为180W的条件下制备的微晶硅薄膜,其晶化率为72.2%,沉积速率为0.48nm/s。     

纳米硅薄膜制备技术进展

本文综述了纳米硅薄膜制备新技术的进展。着重介绍了高氢稀释硅烷蚀刻法，微波氢基团增强化学气相沉积，逐层法和高频数值等离子体化学气相沉积技术制备纳米硅薄膜的沉积过程和生长机制．本文指出氢基团为各项新技术发展的关键并将在今后纳米硅薄膜制备技术发展中起重要作用。     

低温高压快速生长纳米晶硅薄膜中氢的作用

以SiH4/H2为气源,用PECVD沉积技术,在低温(200℃)、高压下(230Pa)下制备出优质纳米晶硅薄膜.研究氢在高速生长纳米晶硅薄膜材料中的作用.实验表明,氢对纳米晶硅薄膜的高速生长起到非常关键的作用.随着氢稀释率由95%提高至99%,薄膜的晶化率由30%增大到70%,晶粒尺寸由3.0nm增大至6.0nm,而沉积速率却由0.8nm/s降低至0.3nm/s.     

镶嵌纳米晶硅的氧化硅薄膜微观结构调整及其光吸收特性

采用等离子体化学气相沉积(PECVD)技术在不同N_2O流量条件下制备了镶嵌有纳米晶硅(nc-Si)的富硅氧化硅(SiOx)薄膜,利用透射电镜(TEM),X射线衍射分析(XRD),傅里叶变换红外(FTIR)和透射光谱技术研究了薄膜中的氢含量和氧含量变化及其对薄膜晶化度、薄膜键合结构和光吸收特性的影响。结果表明,薄膜由nc-Si粒子和非晶SiOx组成,为混合相结构。nc-Si的生长与氧化反应的竞争决定了薄膜微观结构、键合特性以及光吸收特性。随着N_2O流量的增加,薄膜的晶粒尺寸逐渐减小。晶界区过渡晶硅的比例减少,晶粒界面随之消失,带隙呈持续增加趋势。该实验结果为ncSi/SiOx薄膜在新型太阳电池中的应用提供了基础数据。     

氢稀释比对氢化硅薄膜两相结构和电学性能的影响

通过改变氢气对硅烷的稀释比R, 采用等离子体增强化学气相沉积(PECVD)方法制备出具有非晶/微晶相变过渡区的氢化硅薄膜, 并研究了所得硅膜在不同沉积阶段的微观结构和形貌、晶化效果和电学性能。研究结果表明, 当R=10时, 样品呈典型的非晶特性; 随着氢稀释比的增大, 薄膜表现出两相结构, 且衬底表面处的非晶过渡层逐渐减薄, 也即非晶向微晶的转变提前。但XRD结果显示, 硅膜的晶化率和平均晶粒尺寸随着R的增加呈先增后减的趋势, 在R=28.6时达到最大值。另外, 暗电导率和载流子浓度表现出了与晶化率一样的变化趋势, 显示出硅膜的电学性能与微观结构的高度正相关性。     

掺硼纳米非晶硅的太阳能电池窗口层应用研究

本文通过等离子体增强化学气相沉积(PECVD)法沉积p型纳米非晶硅薄膜(na-si:H),系统地研究了掺杂气体比(B2H6/SIH4)、沉积温度、射频电源功率对薄膜结构、光学、电学性能的影响.研究表明,轻掺硼有利于非晶硅薄膜晶化,但随着掺硼量的增加,硼的"毒化"作用又使薄膜变为非晶态;与p型a_si:H相比,掺硼纳米硅薄膜的光学带隙Eopt较高,电导率较高,电导激活能较低,是一种很有潜力的太阳能电池窗口层材料.     

大气压等离子体制备类二氧化硅薄膜的实验研究

本文利用六甲基二硅氧烷(HMDSO)作为硅的先驱粒子,氮或氩气为稀释气体,进行了大气压等离子体化学气相沉积类二氧化硅薄膜的实验研究.运用红外光谱(FTIR)、光电子能谱(XPS)和扫描电镜(SEM)对沉积的薄膜进行结构和表面分析.实验表明,当功率一定时,在低的HMDSO含量下,硅衬底上得到了一层平整、致密、连续的薄膜沉积.红外吸收谱分析呈现出明显的Si-O-Si吸收峰,表明了类二氧化硅结构,其中的[Si]/[O]含量比达到1∶1.56.当HMDSO含量增加时,薄膜中含碳键成分增加,薄膜表面的大颗粒增多.相对地氮气而言,氩气在大气压下更容易获得稳定均匀的等离子体和更大的生长速率/功率比.     

微晶硅太阳电池中的p型层对本征层结构特性的影响

本文采用VHF-PECVD技术制备了系列硅薄膜,通过椭圆偏振技术及拉曼测试手段研究了p型微晶硅层对本征微晶硅薄膜结构特性的影响.实验结果表明:在薄膜生长初期,与玻璃衬底上生长的本征微晶硅薄膜相比,微晶p层上的硅薄膜表面粗糙度较大,非晶孵化层较薄;随本征薄膜厚度的增加,玻璃衬底上生长的本征微晶硅薄膜的粗糙度大于微晶p层上生长的本征微晶硅薄膜,相比之下,微晶p层上的本征微晶硅薄膜生长得比较均匀.     

射频功率对微晶硅薄膜微结构和光电性能的影响

采用射频等离子体增强化学气相沉积(rf-PECVD)技术,在玻璃和硅衬底上沉积微晶硅(μc-Si:H)薄膜。利用拉曼光谱、AFM和电导率测试对不同射频功率下沉积的薄膜的结构特性及光电性能进行分析。研究表明:随着射频功率的增加,薄膜的晶化率和沉积速率也随之增加,而当射频功率增加到一定的程度,晶化率和沉积速率反而减小。薄膜的暗电导率与晶化率的变化情况相对应。     

水性聚氨酯/纳米二氧化硅杂化材料的制备及性能

以三羟甲基丙烷(TMP)为内交联剂,合成了一种内交联的水性聚氨酯(WPU)预聚体,以KH550为偶联剂,加入亲水型纳米二氧化硅(A200),通过溶胶-凝胶过程合成了一种水性聚氨酯/纳米二氧化硅杂化材料(PUSi).通过红外光谱(FT-IR)、热重分析(TG)和透射电镜(TEM)等测试对PUSi的结构和性能进行了研究,并...     

Electrochemical deposition of MoS2 thin films by reduction of tetrathiomolybdate

Molybdenum sulphide was cathodically electrodeposited from aqueous solutions of sodium tetrathiomolybdate. The as-deposited films were X-ray amorphous with a composition, measured by microprobe analysis, close to MoS₂. Annealing these films in Ar resulted in highly-textured films of MoS₂ with the van der Waals planes parallel to the substrate. A small expansion in the c spacing of the annealed films was explained by the presence of oxygen in the crystals. A direct bandgap of 1.78 eV was found for the annealed films.     

Characterizations of spray-deposited lanthanum oxide (La2O3) thin films

A simple and inexpensive spray pyrolysis method was used for the preparation of lanthanum oxide thin films. The films were prepared by spraying 0.1 M lanthanum chloride solution onto the conducting and non conducting glass substrates. The substrate temperature was varied from 523 to 723 K and structural, optical and electrical properties of the films were studied. A photoelectrochemical (PEC) cell was formed using La₂O₃ films as a photoelectrode.     

Characterization of crystalline structure and morphology of NiO thin films

We investigated the relation of sputtering powers with structural and morphological properties of nickel oxide (NiO) thin films. NiO thin films were fabricated by using an rf-reactive sputtering method on Si(100) substrates with a Ni target in a partial pressure of oxygen and argon. The films were deposited by various rf-sputtering powers from 100 to 200 W at room temperature. The phases and crystalline structures of the deposited films were investigated by using grazing incident X-ray diffraction (XRD). The thickness and surface morphology of the films were investigated by using a field emission-scanning electron microscopy (FE-SEM). The different sputtering conditions drastically affected the crystallinity and the surface morphology of NiO thin films. A combined analysis of the data obtained from X-ray diffraction and SEM images demonstrates that the preferred orientation of NiO films tends to grow from (111) to (200) direction as increasing the sputtering power, which can be explained by in terms of the surface energy along the indexing plane in an fcc structure. As increasing the rf power, lattice constants decreased from 4.26 to 4.20 angstroms and samples became high-quality crystals. Under our experimental condition, NiO films prepared at 150 W with 20% partial pressure of oxygen and 7 cm distance from the sample to the target show the best quality of the crystal.     

溅射气压对HfO_2薄膜结构和光学性能的影响

HfO2薄膜的结构和光学性能与反应溅射时使用的气压有很强的依赖关系。薄膜的晶粒生长取向、生长速率和折射率明显受溅射气压的影响。所有的薄膜均为单斜相,晶粒尺寸在纳米量级。薄膜的折射率在1.92～2.08范围内变化,透过率大于85%。结果表明,这些HfO2薄膜很适宜用作增透膜或者高反膜。此外,通过Tauc公式推出光学带隙在5.150～5.433eV范围内变化,表明样品是良好的绝缘体。     

Resistivity and adhesive strength of thin film metallizations on single crystal quartz

Resistivity and adhesive strength were measured for the thin films 450 A Cr-1800 A Au, 450 A Cr-1000 A Mo-1800 A Au, 450 A Cr-1000 A Ni-1800 A Au, 450 A Mo-1800 A Au, 1800 A Au, and 2000 A Al on z-and AT-oriented single crystal quartz substrates in the as-deposited condition as well as after thermal annealing at 380 degrees C and 450 degrees C for 30 min in air or vacuum. The Cr-Au films exhibited significant resistivity increases after thermal annealing which were caused by the interdiffusion of Cr and Au. Barrier layers of Mo or Ni limited such increases after heat treatment. The Mo-Au, Au, and Al films exhibited resistivity decreases following thermal annealing. The mean adhesive strengths of the Cr-Au, Cr-Mo-Au, and Cr-Ni-Au films were excellent in the as-deposited and annealed conditions, ranging from 41 MPa to 70 MPa. The Mo-Au and Au films maintained relatively poor adhesion under all circumstances. Heat treatment improved the poor adhesive strength of the as-deposited Al films to values exceeding 63 MPa. Resistivity and adhesive strengths did not differ significantly between the z- and AT-oriented substrates.     

具有多层结构的聚合物复合薄膜的介电和磁性能

采用旋涂法制备了 Fe3 O4/聚偏氟乙烯(PVDF)复合薄膜(A)、多壁碳纳米管(MWCNT)/PVDF复合薄膜(B)以及纯PVDF薄膜(P)。利用热压法制备具有3层结构的AAA、ABA及APA 复合薄膜。为了探究层状结构对复合薄膜介电和磁性能的影响,制备了单层膜A作为对比(厚度与AAA复合薄膜相同)。分别研究了薄膜的介电和磁性能。结果表明：由于界面效应,同等厚度的AAA复合薄膜较A膜而言具有较高的介电常数;以B和P薄膜替代AAA结构中间层薄膜后,其中ABA复合薄膜的介电常数高于AAA及APA复合薄膜,同时保持较低的介电损耗。对于磁性能,层状结构对复合薄膜的饱和磁化强度及矫顽力均无明显的影响,而ABA复合薄膜的饱和磁化强度高于AAA及APA复合薄膜,且ABA和APA复合薄膜的矫顽力增加。层状结构设计不仅能够调节复合材料的介电性能和磁性能,而且有利于不同纳米填料的分散,为制备多功能聚合物复合材料提供了一定的借鉴作用。     

Development of a mathematical model for the effect of temperature and relative humidity on the water vapour permeability of plastic films

The water vapour permeability constants of three flexible films (LDPE, PET and a laminate of both films) were determined at 20, 30 and 40 °C and from 55 to 90% relative humidities. The relationship between permeability and temperature followed the Arrhenius model for the three films. The relative humidity also influenced the permeability of the films. A mathematical model describing permeance (P/X - the permeability of laminates or films) as a function of external relative humidity and temperature was developed. The model can be used to predict the permeance of the three films at different temperatures and relative humidities.     

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There are conflicting reports in the literature as to whether epitaxial films can be grown over intermediate thin continuous carbon layers. A series of experiments was carried out on the NaClAu system in which the effect of intermediate carbon films on the epitaxy of the gold was studied. For a very limited thickness range of carbon intermediate layers, good epitaxial gold films were formed. The corresponding carbon films were stripped, and examination in the electron microscope showed that the films were continuous and free from holes greater than 10 Å in diameter. A model based on “pseudomorphic islands” in the carbon film is proposed to account for the observations.     

铝阳极氧化膜中温封孔工艺研究

铝阳极氧化膜的常温封孔工艺应用广泛,但厚膜封孔比较困难,染色膜封孔时多数染料都会流色,导致封闭质量不佳.为此,研究了一种新型的铝阳极氧化膜中温封孔工艺,并筛选了抑灰剂、封闭盐及其他辅助成分,研制出MS-05中温封孔剂,其分为A型和B型两种产品,其中A型是无氟、无镍的环保型封孔剂,B型是醋酸镍型封孔剂.与日本同类产品进行对比的结果表明:A型不适用于染色膜的封孔,但对无色和电解着色膜具有优异的封孔质量;B型与日本同类产品等效,适应于包括染色膜在内的所有阳极氧化膜,解决了厚膜封孔及染色膜封孔的问题.此外,还对常温封孔和中温封孔两种类型的封孔工艺的优劣做了分析和讨论.