辅助电场下TeO2-Nb2O5-AgCl系统玻璃的核化与析晶机理研究

在玻璃材料热处理过程中施加辅助电场,如果玻璃相的介电常数小于析出晶相的介电常数,则对玻璃的核化、晶化过程起促进作用;反之则起抑制作用．本文推导了辅助电场与温度场共同作用对玻璃核化、析晶过程的影响机理,研究了辅助电场对TeO2-Nb2O5-AgCl系统玻璃核化与析晶过程的促进作用．结果发现,辅助电场能帮助玻璃在稍低于核化和晶化温度区域的温度下成核和析晶,它可以成为控制玻璃核化和晶化过程的一个“开关”,有可能用以精确控制玻璃中纳米晶体的生长．     

不同形貌低维纳米／微米CdSe／ZnSe的溶剂热法合成

利用溶剂热法．通过添加不同种类的溶剂及改变反应温度、反应时间．成功合成了具有片状、棒状、球技，圆锥花序状等不同形貌的纳米/微米级硒化镉、硒化锌半导体材料.简单讨论了表面活性剂、反应温度及反应时间对产物形貌及尺寸的影响。所得产物进行了扫描电子显微镜（SEM）、透射电子显微镜（TEM）、能谱（EDS）、X射线折射（XRD）等表征.     

不同形貌低维纳米/微米CdSe/ZnSe的溶剂热法合成

利用溶剂热法,通过添加不同种类的溶剂及改变反应温度、反应时间,成功合成了具有片状、棒状、球状、圆锥花序状等不同形貌的纳米/微米级硒化镉、硒化锌半导体材料.简单讨论了表面活性剂、反应温度及反应时间对产物形貌及尺寸的影响.所得产物进行了扫描电子显微镜(SEM)、透射电子显微镜(TEM)、能谱(EDS)、X射线衍射(XRD)等表征.     

GdSe涂层（CdSe／Ni）的烧结工艺对半导体隔膜电极（SnO2.P／CdSe／Ni）性能的

通过Ｘ射线衍射，扫描电子显微镜，透射电子显微镜和高能电子衍射等了由蒸发冷凝法制备的ｎ型半导体材料ＧｄＳｅ超细微粒涂层（ＣｄＳｅ／Ｎｉ）的烧结工艺。     

不同形貌CdSe纳米晶的合成及其形成机理研究

采用水热反应法,通过调节反应时间制备得到了不同形貌的CdSe纳米晶材料,并用TEM、XRD、EDS、XPS等分析手段对其形貌结构进行表征。研究表明,在反应温度为180℃的条件下,所得产物均为六方晶相的CdSe纳米晶,形貌随着反应时间的改变而发生变化:当控制反应时间为2h、5h、10h时,得到的CdSe纳米晶的形貌分别为树枝状、由树枝状到棒状过渡的簇状及棒状。分析了CdSe纳米晶形成的化学反应原理,并运用结晶学原理和相关模型理论对CdSe纳米晶的形成机理及其形貌变化进行了探讨。     

聚苯乙烯微球表面合成CdSe纳米晶

以聚苯乙烯(PS)单分散微球为模板, 利用表面化学沉积, 在PS微球表面合成了CdSe纳米晶. 透射电子显微镜(TEM)观察发现, CdSe纳米晶以岛状形貌分布在PS微球表面, X射线衍射(XRD)分 析显示合成CdSe纳米晶具有立方相结构. 通过对产物形貌的演变过程进行观察分析表明, PS球周围的双电层结构对该形貌的形成起决定作用.     

双温区生长CdSe单晶及其红外表征

硒化镉晶体是一种很有前途的室温核辐射探测器半导体材料,实验采用改进的双温区气相垂直提拉法成功的生长了Φ15mm×40mm,电阻率为107～108(Ω·cm)量级的硒化镉单晶体.对生长的硒化镉单晶体(110)解理晶片进行XRD、红外透过测试,结果显示:硒化镉单晶体完整性好,红外透过率＞62%,表明用二步提纯,在具有较好温度梯度的双温区炉中生长晶体,能有效地控制杂质、缺陷浓度和晶体的化学配比.     

GdSe涂层(CdSe/Ni)的烧结工艺对半导体隔膜电极(SnO_2·P/CdSe/Ni)性能的影响

通过Ｘ射线衍射（ＸＲＤ）、扫描电子显微镜（ＳＥＭ）、透射电子显微镜（ＴＥＭ）和高能电子衍射（ＲＨＥＥＤ）等技术，研究了由蒸发冷凝法制备的ｎ型半导体材料ＧｄＳｅ超细微粒涂层（ＣｄＳｅ／Ｎｉ）的烧结工艺。实验指出，烧结后的ＧｄＳｅ粉体涂层的结晶形态、膜层的致密均匀性以及结晶粒度的尺寸等均与烧结的工艺条件密切相关。将涂在Ｎｉ箔上的ＧｄＳｅ粉体膜层置于氩气氛中，在缓慢升降温的条件下，于４５０～５００℃温度下恒温２ｈ的多次重复烧结，可以获得表面平整致密、在衬底Ｎｉ箔上附着力强的ＧｄＳｅ多晶膜层，以下称ＣｄＳｅ／Ｎｉ为烧结体。将烧结体应用于半导体隔膜电极（（ＳｎＯ２·Ｐ／ＣｄＳｅ／Ｎｉ）中，可有效地改善半导体隔膜电化学伏打电池（ＳＣ－ＳＥＰ电池）的光电化学特性。     

钙铁硅铁磁体微晶玻璃热处理制度的研究

使用XRD、DTA、VSM等分析测试手段对在还原气氛下含少量B2O3、P2O5钙铁硅微晶玻璃的热处理制度进行了较深入的研究。研究发展,预核化处理对于钙铁硅微晶玻璃的晶化无明显作用。900℃作为钙铁硅微晶玻璃的晶化温度较适宜,晶化时间宜8h以上。     

Structural and optical properties of nanocrystalline CdSe and Al:CdSe thin films for photoelectrochemical application

Nanocrystalline CdSe and Al:CdSe semiconductor thin films have been successfully synthesized onto amorphous and FTO glass substrates by spray pyrolysis technique. Aqueous solutions containing precursors of Cd and Se have been used to obtain good quality films. The optimized films have been characterized for their structural, morphological, wettability and optical properties. X-ray diffraction (XRD) studies show that the films are polycrystalline in nature with hexagonal crystal structure. Scanning electron microscopy (SEM) studies show that the film surface is smooth, uniform and compact in nature. Water wettability study reveals that the films are hydrophilic behavior. The formation of CdSe and Al:CdSe thin film were confirmed with the help of FTIR spectroscopy. UV–vis spectrophotometric measurement showed a direct allowed band gap lying in the range 1.673–1.87 eV. Output characteristics were studied by using cell configuration n- CdSe/Al:CdSe |1 M (NaOH + Na₂ + S)|C. An efficient solar cell having a power conversion efficiency of 0.38% at illumination 25 mW cm⁻² was fabricated.     

Photoconductivity and recombination in amorphous Se/CdSe multilayers

Transport and recombination in single layers of a-Se, CdSe as well as amorphous multilayers of Se/CdSe have been studied by measuring temperature dependencies of the photocurrent and the exponent in the intensity dependence of the photocurrent. It has been suggested that the transport: (i) in a-Se was controlled by traps situated at 0.25 eV above the top of the valence band or the localized states of the valence band tail; (ii) in CdSe was controlled by traps at about 0.12 eV below the conduction band. The recombination was considered to be dominated by deep centers in both Se and CdSe layers. Values of around 0.6 eV and 0.7 eV above the valence band have been determined for the position of the centers dominating recombination in CdSe at temperatures lower than 110 K and higher than 200 K respectively. The position of the recombination centers in a-Se has been determined at about 0.97 eV above the valence band. This coincides with the position of the three-fold coordinated Se atoms carrying a positive charge (C₃⁺ defects) determined by other authors.     

Electrodeposition of CdSe on nanopatterned pillar arrays for photonic and photovoltaic applications

This work investigates the electrodeposition of CdSe photonic nanostructures into two dimensional (2D) resist templates generated by X-ray lithography. This templated electrolytic infiltration process is particularly interesting for photonic and photovoltaic applications. Both current and voltage controlled electrochemical depositions have been performed to infiltrate CdSe onto the 2D templates. Followed by the removal of the template, triangular arrays of CdSe pillars or networks with more than 1 μm in height were obtained. The detailed studies of deposition parameters such as applied voltage, current density, deposition time, concentrations of electrolytes and temperatures were carried out to determine the optimum conditions to obtain high quality 2D CdSe photonic crystals (PhCs). The full optical and structural characterization of the CdSe nanostructures showed that the CdSe films prepared have a cubic structure with nanometer grain size. Optical absorption studies reveal a bandgap of 2.1 eV for the thin film grown CdSe, blue-shifted from the characteristic 1.7 eV of bulk CdSe, resulting from size quantization effect. Preliminary optical characterization by a micro-reflectance technique is performed in order to assess the performance of the fabricated samples as 2D PhCs.     

Enhanced electroluminescence in emissive polymer/CdSe double-layer films

We demonstrate that the phase aggregation process can be generally applied to the fabrication of polymer/CdSe double-layer light-emitting diodes (LEDs). The current and luminance characteristics of devices with aggregated CdSe nanoparticles are much better than those of devices with well-dispersed CdSe nanoparticles. It has been found that during the spinning process, aggregated nanoparticles are separated from the polymer and become attached to the polymer film. Aggregated nanoparticles between the emitting layer and the Al cathode can act as a buffer layer, enabling polymer/CdSe-based LEDs to exhibit better luminescence efficiency than that of neat polymer-based LED.     

Electrophoretic deposition of CdSe nanocrystal films onto dielectric polymer thin films

The electrophoretic deposition of cadmium selenide (CdSe) nanocrystal films from a stable hexane suspension onto a dielectric polymer film is reported. The electrodes were prepared by spin casting a ~ 30 nm thick smooth, defect-free, polystyrene film on silicon substrates. Scanning electron microscopy and atomic force microscopy showed that the CdSe films deposited atop polystyrene possessed morphology comparable to CdSe films deposited on the bare silicon electrodes. Factors affecting deposition, such as nanocrystal charging in suspension and wetting of electrode surfaces, are reviewed. This approach to preparing nanocrystal films onto homogeneous dielectric layers will facilitate the fabrication of novel polymer-nanocrystal composites.     

氟化物对CaO-Al2O3-SiO2系玻璃析晶行为的影响

采用DTA、XRD、SEM等现代测试分析手段研究了晶核剂CaF2 对CaO Al2 O3 SiO2 系玻璃析晶行为的影响。结果表明 ,晶核剂CaF2 能有效地促进玻璃的整体析晶 ,在一定热处理制度下 ,可制备出晶粒尺寸为0 .1～ 0 .2 μm的白色微晶陶瓷 ,主晶相为透辉石和硅灰石。随着CaF2 含量的增加 ,透辉石型晶相增多 ,硅灰石型晶相减少。     

核化温度对CaO—Al2O3-SiO2-Fe2O3系微晶玻璃微观结构及性能的影响

本文以钢渣和赤泥为主料,采用熔融法制备了CaO对微晶玻璃物相、微观结构及性能的影响。分析测试结果表明,化温度的升高,主晶相衍射峰先增高后降低,晶相析出量增加,晶玻璃的抗弯强度和耐腐蚀性最好。CaO-Al2O3-SiO2-Fe2O3系微晶玻璃,探讨了不同核化温度微晶玻璃的结晶物相不随核化温度的变化而改变。随着核且析出的晶粒尺寸逐渐增大。当核化温度为770℃时,微