Solution-processed ZnO nanoparticle-based semiconductor oxide thin-film transistors

We have prepared solution-processed oxide semiconductor thin-film transistors using ZnO nanoparticles with various particle shapes. Uniform, dense, thin films were produced by spin-coating ZnO nanoparticle dispersions containing either nanorods or nanospheres. The influence of annealing atmosphere on both nanoparticle-based TFT devices was investigated. XPS analysis revealed that the ZnO particles of the nanorod and nanosphere dispersions have distinct stoichiometries (i.e., molar ratios of Zn:O). The starting particles in turn predetermine the carrier concentration within the annealed ZnO films, which in turn determines whether the device is a semiconductor or metallic conductor, depending upon the annealing atmosphere. Grain structures of the channel layer also play an important role in determining the device performance of the nanoparticle derived ZnO TFTs.     

Structural and electrochemical characterization of Ce0.85Ca0.05Sm0.1O1.9 oxide ion electrolyte with Sr-doped LaMnO3 and SmCoO3 cathodes

This paper reports on the electrochemical properties and chemical stability of a recently developed Ca²⁺ and Sm³⁺-doped oxide ion conducting electrolyte, Ce_0.85Ca_0.05Sm_0.1O_1.9 (CCS), employed in an intermediate temperature solid oxide fuel cell (IT-SOFC) using conventional Sm_0.5Sr_0.5CoO₃ (SSC) and La_0.8Sr_0.2MnO₃ (LSM) cathodes in air at elevated temperatures. The materials were prepared by conventional solid-state reactions using their corresponding metal oxides and salts in the temperature range of 1,200–1,450 °C in air. Powder X-ray diffraction (PXRD) and impedance spectroscopy were employed for phase formation, chemical compatibility, and electrochemical characterization. PXRD studies on 1:1 weight ratio of heat-treated (1,000 °C for 3 days) mixtures of SSC or LSM and CCS revealed the presence of fluorite-type and perovskite-like phases. The area-specific resistance (ASR) value in air was lower for SSC cathodes (4.3–0.15 Ω cm²) compared to those of LSM (407–11 Ω cm²) over the investigated temperature range of 600–800 °C. As expected, a significant increase in ASR was observed in Ar as compared to air.     

Resonance enhanced multi-photon ionization of neutral atoms sputtered with Ga-FIB

Resonance enhanced multi-photon ionization (REMPI) of neutral aluminum atoms sputtered with gallium focused ion beam (Ga-FIB) was studied in terms of substrate temperature and chemical state of the surfaces. Aluminum has the lowest excitation state (3p ²P_3/2) at 112 cm⁻¹ above the ground state (3p ²P_1/2). The results showed that the total REMPI signal intensity of neutral aluminum atoms and the ratio of REMPI signal intensities attributed to ²P_1/2 to ²P_3/2 were increased at higher temperature. On the other hand, the REMPI signal and the ratio were decreased in the case of partially oxidized aluminum surfaces. Considering the result on Al₂O₃, it was confirmed that the REMPI signals of ground state ²P_1/2 and the first excited spate ²P_1/2 could be affected with surface oxidation state.     

石墨炉原子吸收光谱法无标准测定氧化铍中痕量铅

采用样品中加入硝酸镁产抗坏血酸作为混合基体改进剂,塞曼石墨炉原子吸收光谱法测定氧化铍中痕量铅,确定了仪器的工作条件,并实现了无标准测定,测定的相对标准偏差不大于５％,用标准加入法测定铅的回收率为８２％－１１４％。     

氮掺杂石墨烯的制备及其对氧还原反应的电催化性能

以氧化石墨烯（GO）为原料、丙酮肟（DMKO）为还原剂和氮掺杂剂,采用化学还原法制备了不同氮掺杂含量的石墨烯（NG）. 利用场发射透射电子显微镜（FETEM）、紫外-可见（UV-Vis）光谱、傅里叶变换红外（FTIR）光谱、X射线光电子能谱（XPS）、zeta 电位和纳米粒度分析、循环伏安（CV）和旋转圆盘电极（RDE）等手段对材料的形貌、结构、成分和电化学性质进行表征. 结果显示：DMKO能有效地还原GO,且通过调节GO与DMKO的质量比,可以得到不同还原效果的NG,其氮含量范围为4.40%-5.89%（原子分数）;GO与DMKO的质量比为1：0.7时制备的氮掺杂石墨烯（NG-1）在O₂饱和0.1 mol·L^-1 KOH溶液中对氧还原反应（ORR）的电催化性能最佳,其ORR峰电流为0.93 mA·cm^-2,电子转移数为3.6,这归因于其较高含量的吡啶-N增加了材料的ORR活性位点. 此外,石墨化-N由于其较高的电子导电性倾向于产生较高的氧还原峰电流,而吡啶-N较低的超电势倾向于产生较正的氧还原峰电位. 与商用Pt/C相比,该材料展现出了优异的抗CH₃OH“跨界效应”的特性.     

无模板剂合成用于超级电容器的二氧化锰/石墨烯复合材料

以尿素、四水合氯化锰和氧化石墨烯为原料,采用水热法并通过热分解制备了一种具有石墨烯包覆结构的石墨烯-二氧化锰复合材料,利用扫描电子显微镜、X射线衍射、比表面积（BET）、拉曼光谱和热失重等技术对其形貌、晶体结构及表面结构进行了表征;在三电极条件下利用循环伏安法、恒流充放电法和交流阻抗法测试了材料的电化学性能,并考察了不同石墨烯含量对材料比电容的影响. 结果表明,在不添加模板剂的条件下制备的复合材料中二氧化锰是具有介孔结构的α-MnO₂,当复合15%（质量分数）的石墨烯后材料的比表面积从109 m²·g^-1提高到168 m²·g^-1. 复合材料具有更好的电化学性能,在0.2 A·g^-1电流密度下复合材料的比电容达到最大值（454 F·g^-1）,远高于纯二氧化锰的值（294 F·g^-1）. 在2 A·g^-1的电流密度下恒流充放电2000 次后复合材料的比电容保持率为92%.     

Direct Spectroscopic Evidence of the Influence of Chamber Wall Condition on Oxide Etch Rate

The drift of TEOS etch rate has been observed during MERIE oxide etch for the damascene process. The etch rate typically fluctuates between 5300 Å/min and 6000 Å/min. Studies using fluorocarbon-based chemistry show a normal TEOS etch rate when the chamber wall is heavily coated with polymer deposition. On the other hand, a lower etch rate appears when the chamber has less deposition. Hysteresis behavior has been observed during the etch rate of TEOS, as well as emission intensity trends of F, CF _x (x=1~3), and SiF. From the observed emission intensity variation of F, CF _x , and SiF, a model is proposed to explain the impact of chamber wall polymer deposition on the etch rate of TEOS. This model includes a mechanism of etch rate enhancement by embedding oxygen in the chamber wall polymer. From the correlation between etch rate and emission intensity, it clearly shows that F is directly responsible for the etch of TEOS. Compared to F, CF _x plasma chemistry has a closer link to chamber wall polymer formation, but contributes less in the etch of TEOS.     

石墨烯的制备、功能化及在化学中的应用

石墨烯是最近发现的一种具有二维平面结构的碳纳米材料, 它的特殊单原子层结构使其具有许多独特的物理化学性质. 有关石墨烯的基础和应用研究已成为当前的前沿和热点课题之一. 本文仅就目前石墨烯的制备方法、功能化方法以及在化学领域中的应用作一综述, 重点阐述石墨烯应用于化学修饰电极、化学电源、催化剂和药物载体以及气体传感器等方面的研究进展, 并对石墨烯在相关领域的应用前景作了展望.     

Studies on the Thin Film of TiO2, Fe2O3 and SnO2 by the Organometallic-CVD Technique

Pure TiO_2,Fe_2O_3 and SnO_2 are wide-bandgap semiconductors.Their films have high transparency in visible spectral region.These oxide films have been applied to electronics,optoelectronics, solar cells and display devices.A variety of techniques including reactive sputtering,reactive evaporation, ion-beam evaporation and chemical vapor deposition, and hydrolyses of the respective halides or alkoxides have been employed for the growth of thin films of TiO_2,Fe_2O_3 and SnO_2.In     

氧化硅-石墨烯气凝胶介孔复合材料的合成及其对苯的吸附性能

采用水热法快速合成了一种新型介孔氧化硅-石墨烯气凝胶复合吸附材料(MSGA)。通过X射线衍射、扫描电镜等方法对MSGA进行表征。结果表明,经过水热反应和冻干处理后的MSGA材料的介孔结构保持完好,介孔氧化硅在MSGA中的分散具有高度均一性。当介孔氧化硅的含量达到88.2(wt)%时,MSGA的比表面积可达395.5m~2/g。MSGA材料对苯蒸汽的常温常压吸附量为10.77mL/g,是石墨烯气凝胶的13倍,吸附穿透时间达到石墨烯气凝胶的34.4倍。在0.8%的环境湿度下,由于材料表面羟基的亲和性,进一步提升了对苯的吸附。得益于超低密度和丰富的内部孔隙结构,MSGA能够适应高达500mL/min的气流量。上述结果表明,该复合材料在VOCs消除领域具有广阔的应用前景。