n沟增强型InP MISFET研究

在掺Fe的<100>晶向半绝缘 InP上,用 TEOS为源的 PECVD SiO_2作为栅氧化层,以Si~+注入 S.I.InP形成源、漏区,研制成基于 InP/SiO_2界面的n沟增强型 InP MISFET.其饱和区跨导 g_m为6.4mS/mm,沟道有效电子迁移率 μ_(eff)为1400cm~2/V·S,并对 InP MISFET特性及漏电流慢漂移行为作了讨论与分析.     

Promotion Effects of Nickel Catalysts of Dry Reforming with Methane

The promotion effects of nickel catalyst of dry reforming with methane were extensively investigated by means of XRD, SEM, EDX, N₂‐adsorption and H₂‐adsorption. XRD characterization indicated that good dispersion of nickel oxide and MgO promoter is achieved over γ‐Al₂O₃ support. Addition of MgO promoter effectively retards the formation of NiAl₂O₄ phase. SEM and EDX analysis exhibited that the addition of rare‐earth metal oxide CeO₂ effectively promotes the Ni metal dispersion on the surface of the catalysts despite of undesirable self‐dispersion of CeO₂ promoter. Furthermore, the nickel component is gradually dispersed on the surface of the support following the exposure to reaction gas mixture for a period of time. The addition of MgO inhibited the self‐dispersion and promotion effect of CeO₂ on Ni dispersion on the catalysts. H₂ chemisorption revealed that the addition of the alkaline oxide MgO promoter significantly prohibits the metal dispersion on the catalyst. Inappropriate promoter addition can result in sharp decrease of the metal dispersion, N₂‐adsorption indicated that oxide promoter was mostly concentrated on the outer layer of the alumina support while the nickel metal was generally dispersed in the support pores. Addition of promoters contributed to more reduction in mesopore volume.     

Surface transfer doping of semiconductors

Surface transfer doping relies on charge separation at interfaces, and represents a valuable tool for the controlled and nondestructive doping of nanostructured materials or organic semiconductors at the nanometer-scale. It cannot be easily achieved by the conventional implantation process with energetic ions. Surface transfer doping can effectively dope semiconductors and nanostructures at relatively low cost, thereby facilitating the development of organic and nanoelectronics. The aim of this review is to highlight recent advances of surface transfer doping of semiconductors. Special focus is given to the effective doping of diamond, epitaxial graphene thermally grown on SiC, and organic semiconductors. The doping mechanism of various semiconductors and their possible applications in nanoelectronic devices will be discussed, including the interfacial charge transfer and the energy level alignment mechanisms.     

A simple method for fabrication of sole composition nickel hexacyanoferrate modified electrode and its application

Nickel hexacyanoferrate film modified gold electrode was prepared by a simple chemical deposition procedure from a fresh prepared solution containing ferricyanide, Ni²⁺, and sodium nitrate. The resultant films have solo composition and are significantly stable as compared to the electrochemically deposited NiHCF films. For different concentrations of Na⁺ in the solution, the formal potential values of NiHCF shift according to the Nernstian behavior with a slope of 48 mV in the range of 10⁻⁴ to 1.0 M. The NiHCF film was also used for the electrocatalytic oxidation of ascorbic acid. The anodic peak current observed in cyclic voltammetry increased with the ascorbic acid concentration. At a fixed potential under hydrodynamic conditions, the calibration plot was linear over the ascorbic acid concentration range 0.1-12 mM.     

生物质与煤混燃机理:固态沉积特性

为了解在1 200 ℃不同反应时间条件下宜阳煤与水稻秸秆混燃的沉积性质,以18 kW的沉降炉为实验平台,利用扫描电镜及能谱,X射线衍射和电子探针方法对混燃的沉积物进行研究。研究表明,不同的混合比例或者不同反应时间条件下,沉积物中的Si、Al和Ca元素变化不大;表面的钾长石的黏性使沉积物更容易富集,而沉积物内部钾长石使沉积物的结构更加稳定;铝硅酸盐和Fe元素在沉积过程中都起了重要的作用。     

Temperature-response polymer coating for in-tube solid-phase microextraction coupled to high-performance liquid chromatography

The silica nanoparticle (SiO₂ NP)-deposited capillary fabricated by liquid phase deposition (LPD) was bonded by 3-(triethoxysilyl) propyl methacrylate and then modified with poly(N-isopropylacrylamide) (PNIPAAm) by polymerization. The resulting PNIPAAm modified SiO₂ NP-deposited capillary was applied to in-tube solid-phase microextraction coupled to high-performance liquid chromatography (in-tube SPME-HPLC). To investigate the extraction performance of the prepared capillary, diethylstilbestrol (DES) with moderate polarity was selected as the model analyte. Results demonstrate that PNIPAAm modified SiO₂ NP-deposited capillary exhibited obvious temperature responsive character. Finally, the PNIPAAm modified SiO₂ NP-deposited capillary was applied to the analysis of three synthetical estrogens from milk samples. The detection limit of the method was found to be in the range 1.2-2.2 ng/g, and recovery was 71.7-98.9% with relative standard deviations in the range of 2.8-12.6%.     

硅电极/溶液界面开路电位-时间谱和原子力显微镜在化学镀Ag中的应用研究

用开路电位-时间谱技术,表征了在硅（100）表面化学镀银的硅电极/溶液界 面吸附态。所得结果与原子力显微镜在纳米尺寸上的面结构信息分析结果作了对比 。同时也将该结果与循环伏安法（CV）结果作了比较。证明当硅电极表面具有单层 吸附Ag~+离子、表面单层吸附Ag~+离子发生沉积反应、Ag~+离子发生本体沉积时的 开路电位-时间曲线有完全不同的特征。     

Self-assembled structures of alkanethiols on gold-coated cantilever tips and substrates for atomic force microscopy: Molecular organisation and conditions for reproducible deposition

Measurements of surface-liquid interactions (contact-angle goniometry) and tip-surface adhesion forces (atomic force microscopy) combined with infrared spectroscopic studies have been used to investigate surface-preparation and solution-deposition conditions for the reproducible formation of self-assembled molecular structures on gold-coated tips and substrates for atomic force microscopy. Preliminary data show that surface-saturated self-assembled monolayers form reproducibly on prolonged (>20 h) exposure of gold-coated glass substrates to ethanolic solutions of ω-functionalised alkanethiols in the concentration range 80-160 mmol dm⁻³. The data also show that exposure for 16 h to alkanethiol concentrations in the range 160-240 mmol dm⁻³ promote bilayer formation whereas concentrations of 240-320 mmol dm⁻³ result in the deposition of multilayers, the average orientation of which is parallel to that of the first molecular layer; the use of parent 1-undecanethiol solutions at concentrations of 1-80 mmol dm⁻³ results in incomplete monolayer coverage.     

Vapor deposition of ultrathin hydrophilic polymer coatings enabling candle soot composite for highly sensitive humidity sensors

Candle soot (CS) is a desirable carbon nanomaterial for sensors owing to its highly porous nanostructure and large specific surface area. CS is advantageous in its low-cost and facile preparation compared to graphene and carbon nanotubes, but its pristine nanostructure is susceptible to collapse, hampering its application in electronic devices. This article reports conformal coating of nanoscale crosslinked hydrophilic polymer on CS film using initiated chemical vapor deposition, which well preserved the CS nanostructure and obtained nanoporous CS@polymer composites. Tuning coating thickness enabled composites with different morphologies and specific surface areas. Surprisingly, the humidity sensor made from composite with the lowest filling degree, thus largest specific surface area, showed relatively low sensitivity, which is likely due to its discontinuous structure, thus insufficient conductive channels. Composite sensor with optimum filling degree shows excellent sensing response of more than 10³ with the linearity of R² = 0.9400 within a broad relative humidity range from 11% to 96%. The composite sensor also exhibits outstanding sensing performance compared to literature with low hysteresis (3.00%), a satisfactory response time (28.69 s), and a fast recovery time (0.19 s). The composite sensor is fairly stable and durable even after 24 h soaking in water. Furthermore, embedding a humidity sensor into a face mask realizes real-time monitoring of human breath and cough, suggesting promising applications in respiratory monitoring.