Analysis of the generation mechanism of the S-shaped J—V curves of MoS2/Si-based solar cells

Amorphous-microcrystalline MoS$_{2}$ thin films are fabricated using the sol-gel method to produce MoS$_{2}$/Si-based solar cells. The generation mechanisms of the S-shaped current density-voltage ($J$-$V$) curves of the solar cells are analyzed. To improve the performance of the solar cells and address the problem of the S-shaped $J$-$V$ curve, a MoS$_{2}$ film and a p$^+$ layer are introduced into the front and back interfaces of the solar cell, respectively, which leads to the formation of a p-n junction between the p-Si and the MoS$_{2}$ film as well as ohmic contacts between the MoS$_{2}$ film and the ITO, improving the S-shaped $J$-$V$ curve. As a result of the high doping characteristics and the high work function of the p$^+$ layer, a high-low junction is formed between the p$^+$ and p layers along with ohmic contacts between the p$^+$ layer and the Ag electrode. Consequently, the S-shaped $J$-$V$ curve is eliminated, and a significantly higher current density is achieved at a high voltage. The device exhibits ideal p-n junction rectification characteristics and achieves a high power-conversion efficiency (CE) of 7.55%. The findings of this study may improve the application of MoS$_{2}$ thin films in silicon-based solar cells, which are expected to be widely used in various silicon-based electronic and optical devices.     

不同制备工艺钒系SCR催化剂理化及催化性能研究

本文研究了制备工艺对 TiO2-WO3-V2O5- 载体型催化剂理化特性及其在 NH3-SCR 反应中催化性能的影响.通过 XRD、TG/DTA 等分析方法考察了煅烧温度等对催化剂中各组分晶体结构的影响,确定了制备负载型催化剂的最佳煅烧温度为 500℃.不同制备工艺催化剂理化性能的对比表明,多步浸渍法不仅提高了锐钛矿型 TiO2 向金红石型 TiO2 的转变温度,而且使更多的钒氧化物处于较低的价态,有利于提高还原反应的催化性能;催化活性评价试验也表明使用多步浸渍法制备的 SCR 催化剂具有较高的催化活性和更宽的高活性反应温度窗口.最后考察了反应空速对多步浸渍法所制备催化剂 NOx 转化效率的影响,结果表明:随空速的增加,NOx 转化效率逐渐降低.     

Photoelectron spectroscopic study of Li oxides on Li over-deposited V2O5 thin film surfaces

The Li oxides species formed on Li over-deposited V₂O₅ thin film surfaces have been studied by using X-ray and UV induced photoelectron spectroscopy (XPS and UPS). The photoelectron spectroscopic data show that the Li over-deposited V₂O₅ system itself is not stable. Further chemical decomposition reactions are taken place even under UHV conditions and lead to form Li₂O and Li₂O₂ compounds on the surface. The formation of Li₂O₂ causes to arise an emission line at about 11.3 eV in the valence band spectra.     

Magnetospectroscopy of double HgTe/CdHgTe QWs with inverted band structure in high magnetic fields up to 30 T

Magnetoabsorption in far and mid IR ranges in double HgTe/CdHgTe quantum wells with inverted band structure has been studied in high magnetic fields up to 30 T. Numerous intraband and interband transitions have been revealed in the spectra and interpreted within axial 8 × 8 k·p model. Splitting of dominant magnetoabsorption lines resulting from optical transitions from hole-like zero-mode Landau level has been discovered and discussed in terms of a built-in electric field and collective phenomena.     

原子吸收光谱法测定铬基合金中钒

本文研究了用原子吸收光谱法，在笑气－乙炔火焰中，测定钒的最佳条件，不用任何分离手段，以铝盐做干扰抑制剂，消除铬，镍对测定钒的干扰，西方法用于铬基合金中钒的测定，方法简单准确，具有实用意义。     

(Zr,V)N复合膜的结构、力学性能及摩擦性能研究

通过非平衡磁控溅射的方法制备了不同V含量的(Zr,V)N复合薄膜, 采用EDS, XRD, XPS, 纳米压痕仪和摩擦磨损仪等对薄膜的化学成分、微结构、力学性能及摩擦性能进行了研究. 结果表明, V的加入虽未改变ZrN的fcc晶体结构, 但使薄膜的择优取向由ZrN的(200)面转变为(Zr,V)N的(111)面. 随着V含量增加, (Zr,V)N复合膜的硬度略有升高后缓慢降低, 并在含25.8 at.%V后迅速降低. 与此同时, 薄膜的常温摩擦系数亦有小幅降低. 高温摩擦研究表明, (Zr,V)N薄膜在300 ℃时出现V₂O₃, V₂O₅ 在500 ℃后形成, 其含量也随温度的提高而增加. 薄膜的摩擦系数因V₂O₅ 的形成而得到显著降低. 关键词： (Zr,V)N 薄膜 微结构 力学性能 摩擦性能     

Room-temperature and solution-processed vanadium oxide buffer layer for efficient charge injection in bottom-contact organic field-effect transistors

We introduce a room temperature and solution-processible vanadium oxide (VO_x) buffer layer beneath Au source/drain electrodes for bottom-contact (BC) organic field-effect transistors (OFETs). The OFETs with the VO_x buffer layer exhibited higher mobility and lower threshold voltages than the devices without a buffer layer. The hole mobility with VO_x was over 0.11 cm²/V with the BC geometry with a short channel length (10 μm), even without a surface treatment on SiO₂. The channel width normalized contact resistance was decreased from 98 kΩ cm to 23 kΩ cm with VO_x. The improved mobility and the reduced contact resistance were attributed to the enhanced continuity of pentacene grains, and the increased work function and adhesion of the Au electrodes using the VO_x buffer layer.     

Nax/2Bi1−x/2MoxV1−xO4 and Bi1−x/3MoxV1−xO4 New Scheelite-related phases

New Scheelite-related solid solutions of the compositions Na_x/2Bi_1−x/2Mo_xV_1−xO₄ (0≤x≤1) and Bi_1−x/3 Mo_xV_1−xO₄(0≤x≤0.2) have been synthesised by the substitution of Na and Mo at the A and B sites respectively of the ABO₄ type ferroelastic BiVO₄. The phases were characterised using chemical analysis, powder X-ray diffraction, scanning electron microscopy, EDAX, and Raman spectroscopy. While almost a continuous solid solution is obtained for the series Na_x/2Bi_1−x/2Mo_xV_1−xO₄, the absence of Na at the A-site results only in a narrow stability region for the other series, Bi_1−x/3 Mo_xV_1−xO₄ where 0≤x≤0.2. Raman spectra of selected samples at room temperature also suggest that vanadium and molybdenum atoms are disordered at the tetrahedral sites.     

sp3sTight-binding parameters for transport simulations in compound semiconductors

A genetic algorithm approach is used to fit orbital interaction energies of sp3s* tight-binding models for the nine binary compound semiconductors consistent of Ga, Al, In and As, P, Sb at room temperature. The new parameters are optimized to reproduce the bandstructure relevant to carrier transport in the lowest conduction band and the highest three valence bands. The accuracy of the other bands is sacrificed for the better reproduction of the effective masses in the bands of interest. Relevant band edges are reproduced to within a few meV and the effective masses deviate from the experimental values typically by less than 10%.     

A Novel Fabrication Technique of Long Period Fiber Gratings

１ＩｎｔｒｏｄｕｃｔｉｏｎＳｉｎｃｅｔｈｅｄｉｓｃｏｖｅｒｙｏｆｐｈｏｔｏｓｅｎｓｉｔｉｖｉｔｙｉｎｇｅｒｍａｎｏｓｉｌｉｃａｔｅｏｐｔｉｃａｌｆｉｂｅｒｓｂｙＨｉｌｅｔａｌ．ｉｎ１９７８［１］，ｓｉｇｎｉｆｉｃａｎｔｐｒｏｇｒｅｓｈａｓｂｅｅｎｍａ...