核壳型复合半导体纳米粒子的研究

核壳型复合半导体纳米粒子,作为复合半导体纳米粒子材料的一个重要分支,凭借其优异的性质,受到了广泛关注.本文主要介绍了有机/无机和无机/无机核壳型复合半导体纳米微粒及其光学性质、分类、制备方法和应用.并对其发展做了展望.     

半导体纳米粒子／聚合物复合材料及制备方法进展

半导体纳米粒子 /聚合物复合材料是一类新型功能材料。由于它有着特殊的光电物理特性 ,无论是从基础研究的角度或是就其潜在的应用价值而言 ,均引起了科学家们的极大关注。本文介绍了半导体纳米粒子 /聚合物复合材料的概念、结构性能 ,对其制备方法的进展进行了总结 ,并展望了其发展前景。     

Mechanochemical Synthesis and Characterization of Group II-VI Semiconductor Nanoparticles

Synthesis of metal sulfide semiconductor nanoparticles of group II-VI; namely ZnS, PbS, CdS, and CuS; by mechanochemical method was carried out in a high energy ball mill from corresponding metal acetates and sodium sulfide. The samples were continuously milled for 10 h with sample withdrawal at 2 h time interval. Structural properties of nanoparticles were studied by x-ray diffraction (XRD), transmission electron microscope (TEM), and ultraviolet-visible spectra. Particle size distribution and stability of 10 h milled samples were examined using particle size analyzer and Turbiscan. It was found that nanoparticles synthesized by mechanochemical method had mean particle sizes as small as 2–25 nm, low agglomeration, narrow size distribution, and uniformity of particle structure and morphology.     

半导体纳米微粒/聚苯胺复合材料的制备和性能研究

简述了近年来新发展的几种半导体纳米微粒/聚苯胺复合材料的构建方法,总结了半导体纳米微粒/聚苯胺复合材料性能表征的部分工作,讨论了半导体纳米微粒的尺寸大小、粒度分布及复合材料的光学和光电化学性能研究等.     

Synthesis and Characterization of Fe-Doped CdSe Nanoparticles as Dilute Magnetic Semiconductor

Cd_1?x Fe _x Se (0??x??0.1) nanoparticles were synthesized by hydrothermal method. The solubility limit of Fe in CdSe nanoparticles was found to be less than 6?% as obtained from X-ray diffraction (XRD) study. With the increase in doping concentration at and above it, secondary phase of FeSe₂ starts appearing. The presence of Cd, Se, and Fe has been confirmed by energy dispersive X-ray spectroscopy (EDS). The increase in band gap value has been confirmed by UV-visible spectra and the variation in emission intensity of photoluminescence (PL) measurements further indicates the incorporation of Fe in CdSe nanoparticles. Transmission electron microscopy (TEM) reveals the spherical nature of synthesized nanoparticles, and the particle size decreases with increasing Fe doping concentration. Fourier transform Infrared spectra (FTIR) confirm the capping of sodium dodecyl sulfate (SDS) surfactant on pure and Fe-doped CdSe nanoparticles. The synthesized nanoparticles show room-temperature ferromagnetic behavior, and the saturation magnetization value was found to increase with Fe doping concentration.     

自燃烧法合成的ZnO基稀磁半导体纳米颗粒研究进展

稀磁半导体制备方法与磁性起源的研究是当前凝聚态物理的一项热门课题.首先介绍了自燃烧合成法的原理和优点,然后以Co和Mn掺杂ZnO为重点,总结了国内外采用自燃烧法合成的ZnO基稀磁半导体纳米颗粒晶体结构、磁性能相关的研究进展,讨论了所得纳米颗粒磁性能的内在物理机制.通过对自燃烧法合成的更宽掺杂范围ZnO基稀磁半导体纳米颗粒的研究,使我们能够更加系统地了解过渡金属掺杂ZnO材料的结构与磁性能,并探讨所得实验现象的内在物理机制.     

两亲性嵌段聚合物模板制备半导体纳米粒子研究现状

两亲性嵌段聚合物在选择性溶剂中的自组装行为导致其在纳米材料制备过程中具有非常好的应用前景。文中以两亲性嵌段聚合物的基本结构特点及自组装行为为出发点,概述了用于制备半导体纳米材料的两亲性嵌段聚合物的种类及特点,重点介绍了以两亲性嵌段聚合物为模板制备半导体纳米粒子的基本方法及在各种条件下半导体纳米粒子的不同生长机制,并对两亲性嵌段聚合物在制备功能化纳米材料方面的应用进行了展望。     

Structural, Optical and Magnetic Properties of Mn-doped CdS Diluted Magnetic Semiconductor Nanoparticles

Diluted magnetic CdS:Mn nanoparticles were synthesized by the aqueous solution method with different manganese (Mn²⁺) concentrations (x=7?C10?atom?%) at room temperature in nitrogen atmosphere and capped with Thiogelycerol. The X-ray diffraction patterns of CdS nanoparticles with different Mn doping concentration indicated that samples have hexagonal structure at room temperature. Energy dispersive X-ray spectroscopy confirmed incorporative of Mn ions in CdS nanoparticles. UV-Visible spectroscopy is used to investigate optical absorption of Mn-doped CdS. From photoluminescence measurement it was found that the intensity of the luminescence spectra decreases by increasing Mn²⁺ dopant ions at high precursor concentration. Also, the room temperature ferromagnetic behavior of Mn-doped CdS nanoparticles is discussed by using hysteresis measurement results.     

Photothermal Study of Two Different Nanofluids Containing SiO2 and TiO2 Semiconductor Nanoparticles

Thermal and optical properties of two different nanofluids containing SiO₂ and TiO₂ semiconductor nanoparticles were studied by thermal lens spectrometry (TLS) and spectrophotometry. In the case of SiO₂ nanofluids the transmission electron microscopy technique was used to obtain the SiO₂ nanoparticle sizes to investigate the size effect of these nanoparticles on the sample thermal diffusivity which is important in some medical applications such as photothermal-modulated drug delivery systems. On the other hand for the case of TiO₂ nanofluids, the photopyroelectric technique, TLS, scanning electron microscopy, and X-ray diffraction were employed to investigate the concentration effect on the thermal properties of these nanofluids. Thermal diffusivities and effusivities as functions of the TiO₂ nanoparticle concentrations were obtained. From the experimental results, an incremental increase in the thermal diffusivities and effusivities was observed when the nanoparticle concentration was increased, indicating that the nanoparticle concentration is an important factor to be considered to obtain nanofluids with more thermal efficiency which are required for some applications, such as degradation of residual water.     

Conversion of Semiconductor Nanoparticles to Plasmonic Materials by Targeted Substitution of Surface-Bound Organic Ligands

Technical Physics Letters - Plasmonic nanoparticles have become a popularly accepted research tool in optoelectronics, photonics, and biomedical applications. The relatively recently appearing...     

A Versatile Route to Assemble Semiconductor Nanoparticles into Functional Aerogels by Means of Trivalent Cations

3D nanoparticle assemblies offer a unique platform to enhance and extend the functionality and optical/electrical properties of individual nanoparticles. Especially, a self‐supported, voluminous, and porous macroscopic material built up from interconnected semiconductor nanoparticles provides new possibilities in the field of sensing, optoelectronics, and photovoltaics. Herein, a method is demonstrated for assembling semiconductor nanoparticle systems containing building blocks possessing different composition, size, shape, and surface ligands. The method is based on the controlled destabilization of the particles triggered by trivalent cations (Y³⁺, Yb³⁺, and Al³⁺). The effect of the cations is investigated via X‐ray photoelectron spectroscopy. The macroscopic, self‐supported aerogels consist of the hyperbranched network of interconnected CdSe/CdS dot‐in‐rods, or CdSe/CdS as well as CdSe/CdTe core‐crown nanoplatelets is used to demonstrate the versatility of the procedure. The non‐oxidative assembly method takes place at room temperature without thermal activation in several hours and preserves the shape and the fluorescence of the building blocks. The assembled nanoparticle network provides longer exciton lifetimes with retained photoluminescence quantum yields, that make these nanostructured materials a perfect platform for novel multifunctional 3D networks in sensing. Various sets of photoelectrochemical measurements on the interconnected semiconductor nanorod structures also reveal the enhanced charge carrier separation.     

Dynamic Scattering of Light in Liquid-Crystal Cells with Metal–Insulator–Semiconductor Microstructures Containing Gold Nanoparticles

Technical Physics Letters - The possibility of reducing the threshold of the effect of dynamic light scattering in liquid-crystal cells has been demonstrated. The threshold lowering is favored by...     

Semiconductor spintronics

We review recent progress made in the field of semiconductor spintronics, a branch of semiconductor electronics where both charge and spin degrees of freedom play an important role in realizing unique functionalities. We first describe the new spin-dependent phenomena found in semiconductors including carrier-induced ferromagnetism in III-V compounds, followed by an account of our current understanding of such spin-dependent phenomena. Then we summarize the challenges the semiconductor spintronics has to meet in order for it to be a success as "electronics".     

半导体制冷研究综述

半导体制冷主要是帕尔帖效应在制冷方面的应用,半导体制冷的主要优点是:制冷迅速,操作简单,可靠性强,容易实现高精度的温度控制,无污染等.尤其适用于制冷量不大,又要求装置小型化的场合.目前,广泛应用于国防、科研、工农业、气象、医疗卫生等领域,实现对仪器仪表、电子元件、药品、疫苗等的冷却、加热和恒温.本文通过半导体制冷与机械制冷比较说明半导体制冷的优点和特点.针对半导体制冷的特点和应用现状,通过研究国内外的相关文献,从影响半导体制冷效率的主要方面:理论、材料、结构方式、传热方式四个方面进行综述,从中总结了半导体制冷研究的热点和成就,归纳出当前半导体制冷研究存在的问题,提出影响半导体制冷的主要因素即:高优值系数材料,复杂的多参数工况以及冷热端散热方式与设计.为今后进行深入研究半导体制冷提供了可供借鉴的研究方向和方法.