沉积温度对Ti—B—N复合薄膜微结构及力学性能的影响

采用多靶轮流溅射技术，用Ｔｉ和六方氮化硼（ｈ－ＢＮ）反应合成了Ｔｉ－Ｂ－Ｎ薄膜，采用ＸＲＤ、ＴＥＭ和显微硬度计研究了薄膜的微结构及其力学性能。结果表明，室温下沉积的Ｔｉ－Ｂ－Ｎ薄膜为非晶体的Ｔｉ（Ｎ，Ｂ）化合物，其硬度达到ＨＫ２４７０；高温下沉积的薄膜为ＴｉＮ结构类型的Ｔｉ（Ｎ，Ｂ）晶体，薄膜在晶化后硬度略有降低。     

Ti—Si—N纳米晶复合膜微结构的TEM观察

2000年，Veprek等报道了在Ti-Si-N复合膜中获得了80-150GPa的超高硬度，这一超过金刚石薄膜硬度（70-90GPa）的结果令人惊讶并引起竞相研究。对于Ti-Si-N纳米晶复合膜的微结构，目前仅有的Veprek模型认为：不容于TiN的Si3N4相以非晶态形式“润湿”于生长中的TiN晶体表面并阻止其长大，因而复合膜形成厚度小于1mm的非晶Si3N4界面相分隔并包裹直径小于10mm的三维TiN纳米晶的微结构，     

Nb—Si—N混合薄膜的HRTEM观察

Ｖｅｐｒｅｋ等[1] 在ＴｉＮ薄膜中加入Ｓｉ形成的由非晶Ｓｉ3 Ｎ4分隔的纳米晶ＴｉＮ薄膜 (记为ｎ ＴｉＮ ａ Ｓｉ3 Ｎ4) ,呈现出超高硬度而成为近年来超硬薄膜的研究热点之一。ＮｂＮ薄膜具有很高的硬度 ,高的耐磨性 ,耐腐蚀性[2 ] 和良好的热稳定性[3 ] 。ＮｂＮ薄膜中添加Ｓｉ元素也是改善其性能的途径之一。为了深入地研究Ｓｉ对ＮｂＮ薄膜微结构和力学性能的影响及其机理 ,本文采用多靶磁控反应溅射的方法制备了Ｎｂ Ｓｉ Ｎ系混合薄膜 ,研究了Ｓｉ在Ｎｂ Ｓｉ Ｎ系薄膜中的存在形式 ,及其对薄膜的微结构和力学性能的影响。实验所用Ｎ…     

反应溅射Ti-Si-N纳米晶复合薄膜研究

Veprek等报道了采用气相沉积方法获得硬度高达80～105GPa的Ti-Si-N薄膜，令人惊讶!尽管尚无人从实验上重复出这一结果，但大量研究。表明，在TiN或其他过渡金属化合物中加入Si，形成以Si2N4界面相分隔并包裹氮化物纳米晶的微结构的确是一条通过微结构设计获得高硬度薄膜的有效途     

Zr-Si-N纳米晶复合膜的生长结构

近来,三元Me-Si-N复合膜因具有超硬效应而受到广泛关注。迄今为止大量研究集中于Ti-Si-N体系,其他体系报道较少。ZrN薄膜的力学性能与TiN薄膜相近,也是一种得到工业应用的硬质涂层材料。在ZrN薄膜中加入Si形成的Zr-Si-N复合膜可能具有良好的综合力学性能。现有关于Zr-Si-N复合膜的研究表明Si的加入能使薄膜得到强化,薄膜的强化可以归结为Si原子溶入ZrN晶格中所形成的固溶强化或形成了非晶Si3N4层分隔包裹三维ZrN纳米晶的微结构模型。本文研究了Si含量对Zr-Si-N复合膜微结构与力学性能的影响。     

The synthesis and dielectric study of BaTiO3/polyimide nanocomposite films

Polymer-ceramic dielectric composites have been of great interest because they combine the processability of polymers with the desired dielectric properties of the ceramics. A novel, simple method to make thin, homogeneous composite films with varying amounts of ceramic filler content has been proposed. Nanocomposite thick films of barium titanate (BaTiO₃) in polyimide (PI) from 3,3′,4,4′-benzophenone tetra carboxylic dianhydride, 4,4′-oxy dianiline have been successfully prepared by in situ imidization using n-methyl pyrrolidinone as the solvent. The dielectric properties of the nanocomposite films were discussed for various filler volume contents. These nanocomposite films exhibited stable dielectric properties in the various frequency ranges. Films were characterized by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermo gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The curing cycle was optimized using FTIR. XRD results confirm BaTiO₃ particles remain unchanged in the PI matrix and no undesired secondary phases are present in the films. Their glass transition behavior and thermal stability were investigated by DSC and TGA, and the films were stable to 300 °C. Scanning electron microscope images show that the BaTiO₃ phase is well dispersed in the polymer matrix.     

Structural and optical properties of CdS/PEO nanocomposite solid films

In this paper solution mixing and casting of Cd(NO₃)₂·4H₂O and poly(ethylene oxide) (PEO) at different molar ratios (1:100–1:600) followed by hydrogen sulfide treatment were employed to fabricate solid films of cadmium sulfide (CdS)/polyethylene oxide (PEO) nanocomposites. The nanocomposites were found to exhibit uniform distribution of CdS nanoparticles in the polymer matrix without any additional capping agent. Systematic investigations on the role of PEO on the optical properties of CdS are presented. The optical properties of the composites examined by UV–vis absorption spectroscopy show that the band gap of CdS nanoparticles increases from 2.45 eV to 2.54 eV with decreasing concentration of CdS in PEO films. X-ray diffraction pattern shows the broadening in shape of the PEO peaks which is induced by the CdS particles in PEO matrix. The CdS particle sizes ranging from 10 to 20 nm are clearly seen in a transmission electron microscope (TEM). The X-ray photoelectron spectroscopic studies (XPS) also confirm the presence of CdS in PEO. Fourier transform infrared spectroscopy studies using attenuated total reflectance (FTIR-ATR) indicate the influence of Cd²⁺ ion on C–O–C stretching in PEO and confirm the presence of CdS nanoparticles within PEO. Photoluminescence spectroscopy (PL) shows the broad emission due to the presence of surface trapped carrier states.     

Synthesis of ZnO: Ge nanocomposite thin films by plasma gas condensation

In this work, we introduce a new method for the synthesis of Ge nanoparticles embedded ZnO thin films that are considered to be a potential candidate for photovoltaic applications. As opposed to current techniques, for the independent preparation of Ge nanoparticles, we propose using Cluster Deposition Source (CDS), which utilizes gas condensation of sputtered Ge atoms. For the synthesis of ZnO thin film host material conventional sputtering technique is employed. In the proposed technique independently synthesized Ge nanoparticles and ZnO thin films are combined into a composite structure on (100) oriented Si substrates. X-ray diffraction (XRD) patterns of the samples have revealed that Ge nanoparticles preferentially settle on (113) planes on top of the (002) oriented ZnO layer. It is realized that Ge nanoparticles with sizes ranging from 16 nm to 20 nm could be embedded into a well-defined ZnO matrix. In fact, transmission electron microscopy (TEM) studies performed on Ge nanoparticles captured on a Cu grids placed just above the substrate during deposition for about 60 s have manifested that Ge nanoparticles reach to ZnO matrix as clusters composed of particles with sizes of about 7–8 nm and then eventually grow larger due to substrate heating implemented during capping layer deposition. Optical absorption measurements have revealed that Ge nanoparticle inclusion lead to an additional absorption edge at about 2.75 eV along with 3.17 eV edge resulting from ZnO host.     

Influence of the dielectric phase on the photoluminescence spectrum of fractally structured nanocomposite lead selenide films

The factors affecting the behavior of the spontaneous photoluminescence spectra of fractally structured nanocomposite lead selenide films formed on glass substrates with different thermal expansion coefficients have been considered. It is shown that the location of the luminescence peak depends strongly on the strain effect of the glassy dielectric phase on the lead selenide nanoclusters.     

Electroluminescence mechanisms in SiO x N y (Si) nanocomposite films

With a view to creating the Si LED, the mechanisms of electroluminescence (EL) in SiO_xN_y(Si) nanocomposite films with Si nanocrystals embedded in the SiO_xN_y matrix are studied experimentally and theoretically. The most important results are obtained from a Au/SiO_xN_ySi)/p-Si structure having a semitransparent electrode, the oxynitride film containing Si nanocrystals with a mean size of 3–5 nm and a concentration of ～10¹⁸ cm^?3; the measurements are made on a reverse-biased structure (substrate potential negative). Room-temperature EL is observed in the visible and IR ranges; the respective peaks are located at wavelengths of 600–700 and about 1200 nm. The study examines current-voltage characteristics of the structure and the dependence of integrated EL intensity on current, voltage, film thickness, the type of substrate conductivity, etc. The following conclusions are drawn from the experimental and theoretical results: The IR branch is mainly associated with carrier heating, avalanche ionization, and formation of light-emitting microplasmas near the substrate-film interface. The visible branch is linked to (i) hot-electron injection from the substrate into the film and (ii) impact excitation of luminescent centers at nanocrystal-matrix interfaces.     

还原温度对纳米FeCo/Al2O3复合薄膜结构和磁性的影响

采用溶胶-凝胶旋涂法和H2还原工艺制备了纳米FeCo/Al2O3复合薄膜.利用X射线衍射仪、扫描电子显微镜、原子力显微镜及振动样品磁强计研究了还原温度对薄膜结构、表面形貌和磁性的影响.结果表明,随着还原温度的升高,薄膜中FeCo的晶粒尺寸和晶格常数变大,薄膜的饱和磁化强度(Ms)也同时增大,其矫顽力(Hc)则先增大,后...     

Prospects for the application of nanostructured polymer and nanocomposite films based on poly-p-xylylene for micro-, opto-, and nanoelectronics

The experimental results on the synthesis of nanocomposites based on poly-p-xylylene using the gas-phase polymerization on surface are discussed. The data on the structure, electron model, and physicochemical properties of the nanocomposites are presented. The specific properties of the materials under study allow the application in the development and creation of gas chemical sensors, new catalysts, photodetectors, and optical and magnetic media with predetermined permittivities and permeabilities for the polymer optical systems. The possible directions of the further investigation are proposed.