前端接触势垒高度对非晶硅和微晶硅异质结太阳电池的影响

运用AMPS-1D（Analysis of Microelectronic and Photonic Structures） 程序系统分析了前端接触（铟锡氧化物）的势垒分别对非晶硅和微晶硅太阳电池性能的影响,比较了两种影响的差异并分析了具体原因. 研究表明：与微晶硅相比,非晶硅受铟锡氧化物功函数Φ_ITO的影响更加显著. 随着Φ_ITO的增加非晶硅的各项物理性能（如太阳电池效率、填充因子等）得到明显改善,而微晶硅的各项参数虽然也随Φ_ITO增加而改变,但更容易趋于饱和. 模拟结果显示,在实际的太阳电池装备过程中可根据前端电极的性能来选择合适的p型硅材料. 关键词： 铟锡氧化物 非晶硅 微晶硅 计算机模拟     

Adsorption and decomposition of NO on O-covered planar and faceted Ir(2 1 0)

We report on the adsorption and decomposition of NO on O-covered planar Ir(2 1 0) and nanofaceted Ir(2 1 0) with variable facet sizes investigated using temperature programmed desorption (TPD), high-resolution electron energy loss spectroscopy (HREELS), and density functional theory (DFT). When pre-covered with up to 0.5 ML O, both planar and faceted Ir(2 1 0) exhibit unexpectedly high reactivity for NO decomposition. Upon increasing the oxygen coverage to 0.7 ML O, planar Ir(2 1 0) has little activity while faceted Ir(2 1 0) still remains active toward NO decomposition, although NO decomposition is completely inhibited when both surfaces are pre-covered by 1 ML O. NO molecularly adsorbs on O-covered Ir at 300 K. At low NO and oxygen coverage, NO adsorbs on the atop sites of planar Ir(2 1 0) while on the bridge and atop sites of faceted Ir(2 1 0) composed of (1 1 0) and {3 1 1} faces. No evidence for size effects in the decomposition of NO on O-covered faceted Ir(2 1 0) is observed for average facet size in the range 5-14 nm. Our findings should be of importance for development of Ir-based catalysts for NO decomposition under oxygen-rich conditions.     

The interfacial properties of MgCl2 films grown on a flat SiO2/Si substrate. An XPS and ISS study

The interaction between MgCl₂ and SiO₂ was investigated by X-ray photoelectron spectroscopy (XPS), ion scattering spectroscopy (ISS) and contact potential difference (CPD) measurements. A thin SiO₂ layer was grown for this purpose on a Si(1 0 0) wafer and MgCl₂ was applied on this support at room temperature by evaporation under UHV conditions. It was found that magnesium chloride is deposited molecularly on the SiO₂ substrate, growing in layers and covering uniformly the oxide surface. The interaction with the substrate is initially very weak and limited to the interfacial layer. Above 623 K, most of the molecular MgCl₂ is re-evaporated and the interfacial interaction becomes stronger, as Mg-Cl bonds in the remaining sub-monolayer chloride break and Cl atoms desorb. This leaves on the surface sub-stoichiometric MgCl_x, which interacts with oxygen atoms from the substrate to form a complex surface species. At 973 K all Cl atoms desorb and Mg remains on the surface in the form of an oxide.     

Synthesis of VO2 (B) nanorods for Li battery application

Vanadium dioxide nanorods were synthesized through a hydrothermal reaction from V₂O₅ xerogel, poly(vinyl pyrrolidone) (PVP) and lithium perchlorate (LiClO₄). The prepared samples were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical discharge–charge cycling in lithium battery. SEM images reveal the nanorods to have dimensions on the order of 1–3 μm in length and 10–50 nm in diameter. The measured initial discharge capacity of the lithium battery with a cathode made of VO₂ (B) nanorods was 152 mA h/g.     

中温固体氧化物燃料电池的基本性质测量

介绍了固体氧化物燃料电池的工作原理,测量了中温薄膜固体氧化物燃料电池的开路电压、放电曲线及功率曲线,并分析了电池内阻随电流密度的变化.     

基于非色散紫外算法的一氧化氮气体检测与分析

提出了一种基于非色散紫外(NDUV)算法,利用光电二极管阵列(PDA)探测器和光谱仪检测一氧化氮气体的分析方法。通过对比分析不同积分次数下一氧化氮吸收谱和无吸收谱内不同波长宽度的总光强,引入光源影响因子F和吸收谱因子B,得到吸光度与浓度的拟合方程及相关系数。结果表明,采用合适的拟合阶数、拟合波长宽度和分析方法,吸光度与浓度的二阶拟合相关系数可达0.999 9以上, 通过拟合方程所获得的待测气体浓度与标准值浓度的误差在3%以内。     

Effect of substrate temperature on structural, optical and electrical properties of pulsed laser ablated nanostructured indium oxide films

Nanocrystalline indium oxide (INO) films are deposited in a back ground oxygen pressure at 0.02 mbar on quartz substrates at different substrate temperatures (T_s) ranging from 300 to 573 K using pulsed laser deposition technique. The films are characterized using GIXRD, XPS, AFM and UV-visible spectroscopy to study the effect of substrate temperature on the structural and optical properties of films. The XRD patterns suggest that the films deposited at room temperature are amorphous in nature and the crystalline nature of the films increases with increase in substrate temperature. Films prepared at T_s ≥ 473 K are polycrystalline in nature (cubic phase). Crystalline grain size calculation based on Debye Scherrer formula indicates that the particle size enhances with the increase in substrate temperature. Lattice constant of the films are calculated from the XRD data. XPS studies suggest that all the INO films consist of both crystalline and amorphous phases. XPS results show an increase in oxygen content with increase in substrate temperature and reveals that the films deposited at higher substrate temperatures exhibit better stoichiometry. The thickness measurements using interferometric techniques show that the film thickness decreases with increase in substrate temperature. Analysis of the optical transmittance data of the films shows a blue shift in the values of optical band gap energy for the films compared to that of the bulk material owing to the quantum confinement effect due to the presence of quantum dots in the films. Refractive index and porosity of the films are also investigated. Room temperature DC electrical measurements shows that the INO films investigated are having relatively high electrical resistivity in the range of 0.80-1.90 Ωm. Low temperature electrical conductivity measurements in the temperature range of 50-300 K for the film deposited at 300 K give a linear Arrhenius plot suggesting thermally activated conduction. Surface morphology studies of the films using AFM reveal the formation of nanostructured indium oxide thin films.     

Synthesis and Characterization of TiO2 Doped ZnO Microtubes

以氯化锌和硫酸钛为原料,通过湿化学法成功制备了钛掺杂氧化锌微米管. 以粉末X射线衍射仪、场发射扫描电子显微镜、光致发光系统对样品进行了表征. 结果表明,未经掺杂的氧化锌微管具有良好的六方中空结构. 在TiO₂/ZnO比率小于5%时,钛掺杂和未掺杂氧化锌管具有相近的尺度,外表光滑,近于圆柱形. 当TiO₂/ZnO比率大于5%时,生成一种由ZnO, Ti₃O₅和TiO组成的多相混合物. 钛掺杂氧化锌在光催化降解甲基橙溶液效果明显.     

Mechanical and electronic properties of stoichiometric silicene and germanene oxides from first‐principles

Using first‐principles calculations, we investigate the fully oxidized silicene and germanene with stoichiometric ratio Si:O/Ge:O = 1:1. For both compounds, the zigzag ether‐like conformation (z‐sSiO/z‐sGeO) is found to be the most energetically favorable structure. These z‐sSiO and z‐sGeO nanosheets have prominent elastic characteristics, which even exhibit an unconventional auxetic behavior with negative Poisson ratios. After oxidation, the semi‐metallic nanosheets are transformed into semiconductors with narrow direct band gaps. Due to the anisotropic mechanical and electronic properties, the z‐sSiO and z‐sGeO possess an axially high intrinsic charge mobility up to the order of 10⁴ cm²/Vs, which is comparable to that of graphene nanoribbons. Our studies demonstrate that the silicene and germanene oxides have peculiar mechanical and electronic properties, which endow these nanostructures for potential applications in nanoelectronics and devices. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The 2D Rancieite-type manganic acid and its alkali-exchanged derivatives: Part I — Chemical characterization and thermal behavior

The 2D Rancieite type manganic acid was prepared by reduction of KMnO₄ in acidic medium. Its ion exchange behavior allows to prepare alkali derivatives. All compounds were characterized with use of a combination of X-ray diffraction, chemical analyses, TGA, magnetic measurements and spectroscopic techniques. The evolution of their chemical composition versus temperature was studied between 180 and 400 °C. It shows that the dehydration process is partly reversible in these compounds whereas the weak reduction is irreversible. The 2D Rancieite-type manganic acid is readily different from a Birnessite-type phyllomanganate, as shown by several features: the interlayer distance, the ion exchange capacity, the thermal behavior, the interlayer cation content, the manganese average oxidation state, the magnetic behavior and the IR spectrum.