第Ⅵ族元素半导体纳米线的可控合成及其纳米电子学器件研究

采用化学液相反应,以亚硒酸或者原碲酸为原料,合成出尺寸均匀、高结晶度的硒、碲纳米线.高分辨电镜分析结果表明:合成的硒、碲纳米线均为三方晶单晶结构,生长方向沿其螺旋轴即[001]方向生长.结合光刻、电子束刻蚀技术,分别制备了硒、碲纳米线场效应晶体管器件(FET).对器件测试的结果显示:硒和碲纳米线均为P型半导体,其相应的空穴迁移率分别为30.7,70cm2V-1 s-1.这对新型纳米线电子学器件的开发应用具有重要意义.     

超声方法合成硒纳米线（英文）

用超声的方法合成了硒纳米线.场发射扫描电镜（FESEM）结果表明产物的形貌比较均一.产物的结构通过透射电镜（TEM）和X-射线衍射仪（XRD）进行了进一步表征.TEM和XRD光谱的结果证明了所得硒纳米线为单晶结构且沿着[001]方向生长.所得硒纳米线在671nm处有一紫外光谱吸收峰,通过对光谱的计算,硒纳米线的能带为1.66eV.基于一系列的生长过程,提出了硒纳米线的生长机理：硒粉溶解溶液中产生自由硒原子;当硒原子浓度过高时,硒原子结晶形成t型硒种子;由于各向异性晶体结构,连续提供的硒原子进入结晶种子形成线性纳米结构.此外,溶解和再结晶使α型硒转化为更稳定的t型硒.超声波可以提供适当的能量来调整这动态的平衡溶解和再结晶,进一步加快这一转变.     

第VI族元素半导体纳米线的可控合成及其纳米电子学器件研究

采用化学液相反应,以亚硒酸或者原碲酸为原料,合成出尺寸均匀、高结晶度的硒、碲纳米线。高分辨电镜分析结果表明：合成的硒、碲纳米线均为三方晶单晶结构,生长方向沿其螺旋轴四[001]方向生长。结合光刻、电子束刻蚀技术,分别翻备了硒、碲纳米线场效应晶体管器件（FET）。对器件测试的结果显示：硒和碲纳米线均为P型半导体,其相应的空穴迁移率分别为30．7,70cm^2V^-11s-1。这对新型纳米线电子学器件的开发应用具有重要意义。     

AZO晶种层对ZnO纳米线生长及紫外光电导性能的影响

采用溶液化学法实现了在Zn(NO3)2/C6H12N4混合溶液中ZnO纳米线在AZO薄膜修饰过衬底上生长。AZO薄膜由射频磁控溅射法制备,通过溅射时间和基底温度的变化改变薄膜形态,重点研究了不同薄膜形态对ZnO纳米线形貌和结构的影响,最终在溅射2h、基底温度250℃晶种上得到垂直于衬底、高度平行取向的ZnO纳米线阵列。在此基础上研究了不同形貌ZnO纳米线阵列的紫外光电导性能差异。结果表明,垂直生长的纳米线较倒伏纳米线紫外响应迅速,分析认为是紫外光照下曝光面积不同造成的。     

三方晶硒纳米线的大面积合成及其场效应晶体管特性

采用液相反应成功制备了高质量硒纳米线。利用透射电镜（TEM）、高分辨透射电镜（HRTEM）以及X射线衍射仪（XRD）研究了纳米的形貌结构特征。结果表明,硒纳米线为单晶结构,生长方向沿[001]面,平行于螺旋轴。结合光刻技术及磁控溅射镀膜技术,成功制备了硒纳米线场效应晶体管器件。初步测试表明,这种硒纳米线为p型半导体。     

Se及Cu2Se纳米线的大面积合成及其纳米电子学器件性能

通过液相化学反应制备了高质硒(Se)纳米线,同时以Se纳米线为模板,合成了CuzSe纳米线.利用透射电镜(TEM)、高分辨透射电镜(HRTEM)以及X射线衍射仪(XRD)研究了纳米线的形貌结构特征.结果显示,Se纳米线为单晶结构,生长方向沿其[001]面.结合先进的光刻技术及磁控溅射,成功制备了Se和Cu2Se纳米电子学器件.初步测试表明,这种Se纳米线为P型半导体,而Cu2Se纳米线则表现出明显的相变行为.这些发现有利于开发纳米线场效应晶体管以及相变存储器件方面的应用.     

富硒产品相关标准的技术动态分析

该文对国内外富硒相关标准进行了梳理,从标准中硒的检测技术发展、不同方法间的异同,以及每一种检测原理的灵敏度、准确度和精密度等方面对硒的检测方法标准进行了动态追踪和系统分析,同时对富硒产品标准中覆盖的产品范围、不同产品的硒含量要求和其他主要技术要素进行了比较归纳,最后结合我国富硒产业的发展实际提出了硒形态分析检测的必要性和制定相关检测方法标准,以及在产品标准中增加硒形态要求技术要素的合理化建议,这对规范我国富硒产品的检测和富硒产品标准的科学化制定具有重要的指导和借鉴意义。     

碳纳米管填充金属Ag纳米线及其机理研究

通过湿化学法将金属Ag成功填入碳纳米管,填充物的形态为纳米线状.用浓硝酸通过沸点回流法对碳纳米管进行处理,处理后不但除掉了其表面的杂质,而且碳纳米管端帽打开并明显被切短.AgNO3溶液通过毛细作用进入开口后的碳纳米管中,在450℃用H2进行还原,还原后碳纳米管被Ag纳米线填充,Ag纳米线直径为20～40nm,长度100nm～10μm.通过透射电镜(TEM)和X射线衍射(XRD)分析研究了Ag纳米线的微观形态和结构.在实验基础上探讨了金属Ag纳米线的形成机理.     

强静磁场对溶剂热合成纳米Bi形态的影响

研究了强静磁场对溶剂热合成纳米Bi形态的影响.实验中选用乙二醇或乙二醇与乙醇的混合液作溶剂、硝酸铋作铋源.结果表明,磁场能促进Bi纳米呈各向异性生长,并诱导合成纳米线.随着磁场强度的提高,产物中纳米线的比例逐步增大;反应温度越高,产物中获得全部纳米线所对应的磁场强度越低;在150℃、磁场强度达到12T时,产物中没有得到全部纳米线,在180℃和210℃时,产物中全部纳米线所对应的磁场强度分别为12T和8T.采用乙二醇与乙醇的混合液作溶剂时,产物中纳米线所对应的磁场强度提高.最后讨论了磁场诱导合成Bi纳米线的原因.     

硒的总量及形态分析综述

综述了近年来硒总量及形态分析研究领域所取得的进展,主要包括:样品前处理技术、形态分离技术中液相色谱分离、毛细管电泳分离、气相色谱分离的优缺点;硒总量分析中氢化物发生原子吸收光谱(HG-AAS)、石墨炉原子吸收光谱法(GF-AAS)、紫外及可见分光光度法、荧光法、电化学法、中子活化技术等的优缺点和各种硒形态检测中HPLC-ICP-MS及ICP-MS的研究现状,同时展望了硒的形态分析技术.     

A new hydrothermal route to nano- and microstructures of trigonal selenium exhibiting diverse morphologies

High purity single crystalline trigonal selenium (t-Se) with different morphologies (wires, rods, flowerlike, and hollow spheres) have been synthesized under hydrothermal conditions through simple one-step at lower temperature (120 °C) using in situ generated sulphurous acid as a new reducing agent. It is noted that the experimental parameters such as reaction duration, temperature and surfactants have an effective and important influence on the formation of different morphologies. The phase analysis, purity, morphology and optical properties of the as obtained products have been characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis spectroscopy, respectively. A possible reaction scheme as well as growth mechanism has been proposed for the formation of t-Se nanowires.     

Selenium nanowires and nanotubes synthesized via a facile template-free solution method

Trigonal selenium (t-Se) nanowires and nanotubes were successfully prepared on a large scale via an environment-friendly synthetic process, in which no templates or surfactants were employed. These t-Se nanowires having a width of 70-100 nm and length up to tens of micrometers were synthesized in absolute ethanol at room temperature, while t-Se nanotubes with outer diameter ranging from 180 to 350 nm were obtained at 85 °C in water system. SEM and TEM analyses of the samples obtained at different stages indicated that the formation of these t-Se 1D nanostructures was governed by a “solid-solution-solid” growth process. The amorphous Se (a-Se) nanoparticles were initially generated and then would transform into crystal seeds for the subsequent growth of nanowires or nanotubes. Detailed experiments found that temperature and solvents as well as concentrations of starting materials were crucial to the formation of final morphology.     

Surface energy-controlled in-plane growth of t-Se nanowires transformed from a-Se colloids

This study investigated the surface energy-controlled transformation of amorphous Se (a-Se) colloids into trigonal Se (t-Se) crystals on solid substrates. Hydrophilic surfaces generated nanowires laterally grown along the surface of the substrates, while on hydrophobic surfaces the nanowires on the colloidal surface were randomly oriented. The ripening was considered to govern the growth of t-Se nanowires. The in-plane growth of the nanowires along the substrates made possible the creation of a chemically interconnected nanowire network because the nanowires made branches on meeting other a-Se colloids and formed chemical junctions on encountering other growing nanowires.     

Selective synthesis of copper nanoplates and nanowires via a surfactant-assisted hydrothermal process

A facile solution-phase process has been demonstrated for the selective preparation of single-crystalline Cu nanoplates and nanowires by reducing Cu⁺ with ascorbic acid (VC) in the presence of cetyltrimethylammonium bromide (CTAB) or cetyltrimethylammonium chloride (CTAC). To study the formation process of nanoplates and nanowires, samples obtained at various stages of the growth process were studied by TEM and XRD. The possible mechanism was discussed to elucidate the formation of different morphologies of Cu nanostructures. UV–vis spectra of the Cu nanoplates and nanowires were recorded to investigate their optical properties, which indicated that the as-prepared Cu nanostructures exhibited morphology-dependent optical property.     

Synthesis and growth mechanism of selenium nanowire bundles via a polymer-controlled chemical route

This article describes a polymer-controlled chemical method for synthesis of trigonal selenium (t-Se) nanowire bundles in the presence of poly(vinyl alcohol) (PVA) at 100 degrees C. Electron microscope images show that Se nanowires have diameters of 30-50 nm and lengths of up to a few tens of micrometers. TEM images display the direct evidence for the growth process of single-crystalline Se nanowire bundles, which suggested that Se nanowire bundles were directly converted from the initial amorphous Se micro-particles in the presence of PVA. UV-Vis absorbance of t-Se nanowire bundles revealed that the bandgap and absorbance peaks displayed larger blue shifts relative to those of bulk t-Se.     

Study on the effect of surfactants on morphologies of trigonal selenium in microfluidic reactor

The influence of the surfactants on the morphologies of trigonal selenium (t-Se) submicrostructures was studied in a two-step microfluidic system, which is composed of a glass microchip for preparing spherical amorphous selenium (a-Se) colloids coupled with a poly(methyl methacrylate) microchip for transferring a-Se into its t-Se seeds under sonication. The selenious acid containing surfactants and hydrazine solutions were delivered through the two-inlets of the glass microfluidic chip. Submicro-rods, -wires as well as -tubes of t-Se were obtained by simply varying the coexisted surfactants. The as-synthesized products were characterized by powder X-ray diffraction (XRD), Raman spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED).     

羧甲基纤维素钠模板法制备纳米硒

报道了羧甲基纤维素钠存在下制备纳米硒的方法,得到了球形、棒状和线状纳米硒。研究了反应时间、反应物浓度、温度、超声等实验条件对产物粒度大小、形貌的影响,采用光谱法、透射电镜、扫描电镜、X射线衍射等手段对产物进行了表征。     

Bioprocess-inspired preparation of silica with varied morphologies and potential in lithium storage

As one of the most delicate bioprocesses in nature,biosilicification is closely related to biosilica with various morphologies,and has provided abundant inspiration to materials synthesis.In the present study,to explore the biosilica formation process and fabricate silica with an exquisite microstructure for lithiumion battery (LIB) electrodes,a bacterial phage (M13) is used as a biotemplate to synthesize silica with diverse morphologies: cylinders,hexagonal prisms,assemblies of smaller cylinders and nanowires.A facile ethanol bath method is conducted to coat the nanowires with nitrogen-containing carbon and carbon-coated Si02 nanowires with mesochannels (C@msSiO2NWs) are first used as anode materials for LIBs.Attributed to the uniform carbon coating and parallel mesochannel structure,the electronic conductivity and capacity to accommodate volume variations were significantly improved.In the electrochemical performance test,the composites calcined at 750 ℃ (C@msSiO2NWs-750) show an impressive capacity of 653 mA h g-1 at a current density of 500 mA g-1 and stability (1000 cycles).In view of the electrochemical test outcomes,the preparation of a sophisticated structure with an outstanding potential is easily achieved via a biomimetic strategy.     

Solvothermal fabrication of uniform silver nanowires

Conventional polyol synthesis has been widely used for the preparation of silver nanostructures with different morphologies. However, there is a drawback that it is difficult to control the reaction parameters for shape-controlled synthesis of silver nanostructures, such as the rate of the addition of silver ions to the solution. In this paper, we combine polyol process and solvothermal method for easily synthesizing silver nanostructures. Importantly, the introduction of cuprous chloride (CuCl) to the reaction leads to increasing the population of twinned Ag seeds (required for wire growth) at the expense of that of single Ag seeds. Silver nanowires (Ag NWs) with uniform width (~80?nm in width) can be obtained in the presence of poly(vinyl pyrrolidone) (PVP). Some other parameters, such as the reaction temperature and molar ratios of the repeating unit of PVP to AgNO₃ (R), also have been discussed. A possible mechanism is put forward to understand the evolution of silver nanostructures.     

8-羟基喹啉铝纳米结构的可控制备

利用简单的物理气相沉积制备了多种纳米结构的8-羟基喹啉铝(AlQ3),主要考察了温度对其微结构的影响.运用傅立叶红外光谱仪、环境扫描电子显微镜、紫外光致发光仪等对其进行了结构、形貌和光致发光特性的研究.结果表明:成功制备了AlQ3纳米链,AlQ3纳米片,AlQ3微米球与纳米线的复合结构.PL谱没有明显的变化,可能是因为AlQ3分子间结合力是较弱的范德华力.