TiN膜的电子显微分析

由于TiN膜具有耐磨、搞腐蚀、导热性好的特点,所以近十几年来人们在此方面作了大量研究工作。认为TiN膜的晶体结构是影响其性能的主要因素。Mathews等人指出在相同硬度下,具有(200)取向比(111)取向的Tin膜更耐磨。而valvoda指出取向程度越低硬度越高。所以说研究膜的取向问题是十分必要的。我院薄膜研究室从87年开始,就对射频等离子体化学气相沉积TiN膜进行研究。本文就是采用该室的Tin膜,对不同沉积时间的膜进行TEM、SEM和X-射线衍射分析。样品制备:1)Tin膜的制备是13.56HZ射频等离子体化学气相沉积的TiN膜。2)TEM样品的制备     

镁铝锌钇合金微结构的电子显微研究

添加适量稀土元素钇后,镁铝合金高温力学性能会得以改善。本文利用光学显微镜(OM)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM),对693 K保温24 h的Mg-9.0wt.%Al-2.2 wt.%Zn-6.1wt.%Y铸态合金样品的微结构进行了研究。实验结果表明,显微组织相组成是基体α-Mg、晶界处γ-Mg17Al12、晶胞内的Al2Y、τ-Mg32(Al,Zn)49及-Al5Mg11Zn4相。确定了-Al5Mg11Zn4相与α-Mg基体间的取向关系是(10 10)α//(106),[51053]α//[010]。     

γ-MnFe（Cu）合金孪晶结构的电子显微分析

γ-MnFe（Cu）基合金存在优良的阻尼性能及磁控形状记忆效应，这些怀能与其反铁磁转变和马氏体转变耦合产生的fct孪晶有关。由于该fct结构的四方度很小（1-c/a大约为0.03），因而一直没有直接支持该假设的电子衍射照片，有人甚至认为该结构无法通过电子衍射来判别。我们通过对γ-MnFe（Cu）金属薄膜进行细致的操作，获得了与该孪晶结构对应的电子衍射花样。     

在长期室温时效中NiAl3和Ni2Al3合金相成分与结构的变化

NiAl3和Ni2Al3是Ni-50wt．％Al二元合金中的两个主要合金相。已经观察到在离子减薄过程中这两个合金相的化学成分会发生变化。本文对放置4年后的Ni-50wt．％Al合金进行了TEM／EDS和HREM研究，观察到在室温时效后两个合金相成分和结构的变化。     

用扫描电子显微分析仪研究铁基非晶合金的晶化

本文用配有X射线能量色散谱仪、电子背散射衍射系统的场发射扫描电子显微镜研究了铁基非晶合金的晶化。试验选用Fe、Ni、P、Cu元素粉末及FeNb、Fe-B中间合金按原子分数配成Fe52、Ni15、CuNb2P14B6成分进行机械合金化试验。分析所用仪器为FEI公司的Sirion型场发射扫描电镜、EDAX公司的GENISIS X射线能量色散谱仪及TSL电子背散射衍射分析系统。     

脉冲化学镀非晶态合金镀层组织结构的研究

本文采用ＴＥＭ和Ｘ射线衍射仪分析研究脉冲化学镀高磷镍合金镀层及经不同温度加热时镀层组织结构的转变。结果表明：脉冲化学镀非晶态镀层组织结构细致，非晶态结构更具无序密堆性，即短程有序的尺度更小；此外，脉冲化学镀非晶态镀层的热稳定性高于化学镀镀层的热稳定性，即晶化温度向高温推移。两种镀覆工艺的镀层经热处理后的时效析出相是一致的。     

分子束外延GaN/GaAs立方相异质结构的电子显微分析

运用透射电子显微镜分析了分子束外延的立方相ＧａＮ／ＧａＡｓ异质微观结构．在ＧａＮ外延层中,观察到大量的、不对称的｛１１１｝面缺陷（层错和微孪晶）,以及失配位错在该大失配界面上的非优化排列,并对面缺陷的生成机理进行了讨论     

Fe85Ga15合金的电子显微结构研究

磁致伸缩材料广泛应用于各种各样的传感器和伺服机构器件,Fe-Ga合金以其作为磁致伸缩材料的潜在应用前景已经引起研究人员的注意。Fe-Ga合金的磁致伸缩效应很强,归因于晶体中存在着Ga原子的不对称形状团簇,其导致的四方格子结构在Fe-Ga合金的磁致伸缩特性中起了关键的作用。     

Al10Cu10Fe1相低温变体Ф2相结构的电子显微分析

1939年，Bradley等最早对Al-Cu-Fe三元系统进行了系统研究。他们鉴定出4种热力学上稳定的、结构未确定的三元化合物相，分别是Al5Cu2Fe，称为ψ相；Al7Cu2Fe，称为ω相；Al10Cu10Fe，称为φ相；Al18Cu10Fe，称为χ相。迄今，除了χ相未被进一步确认外，其余三相及其结构都已被确认，尽管φ相的结构还有争论。     

Ly12合金金相组织与机械性能分析探讨

本文阐述了Ly12合金的过烧起始温度是一个狭小区间内。过烧起始温度下限为502℃，过烧起始温度与加热时间的关系以及过烧前后的组织与力学性能变化规律进行探讨，还对产生产过程中的Ly12合金淬火工艺提出改进意见。     

电脉冲下黄铜粗晶合金发生纳米相变的TEM观察

电脉冲对物态变化有重大影响的事实屡见报道,如对非晶结构的弛豫和晶化[1]等,但其影响机制尚不很清楚。电脉冲作用时间虽很短,却使材料结构和性能发生一些特殊的变化,这种非平衡过程中的结构变化一直是材料科学界感兴趣的课题,并且有一定实际意义。本文作者首次在单脉冲高密度电流处理的常规材料H62粗晶黄铜中发现了纳米相变的产物,并作了机制上的探索,为寻找一种新的更经济更有效的制备纳米材料的方法奠定了初期的实验基础。本文采用工业用冷轧铜带H62,厚度为0.102mm,名义成分为(物质质量分数/wt.%):Cu61.75、Zn37.5、其余杂质0.75。将铜…     

MOSFET's negative transconductance at room temperature

Negative transconductance is reported for the first time at T=300 K for NMOS transistors fabricated with different technologies and oxide thickness in the 3-20 nm range. The effects of drain bias, channel length, oxide thickness as well as substrate doping and bias on the phenomenon are investigated. The results are interpreted in terms of surface-roughness limited mobility, and parameters for mobility modeling at high effective fields are extracted     

Crystallographic study on self-annealing of electroplated copper at room temperature

Self-annealing in electroplated Cu films is the dramatic evolution of the microstructure in electroplated Cu near room temperature, and it occurs during a transient period of hours following the electroplating process. This study discusses the change of grain size and orientation in self-annealing of Cu films electroplated by an additive-free sulfate bath using X-ray diffraction and electron backscatter diffraction techniques. We found that the self-annealing started at the interface between the substrate and the electroplated Cu film. Immediately after the electroplating process, orientation of the Cu grains in the region near the interface was similar to that of the substrate. This indicates that the grain growth was affected by the substrate. Then, grain growth and change in orientation of the electroplated Cu film at room temperature became independent from the orientation of the substrate. The electroplated Cu film had many high-angle-grain boundaries (HAGBs) before incubation, and the fraction of HAGBs reduced as incubation time increased. Self-annealed Cu grains in the electroplated Cu film had many multiple twins, which came from low stacking-fault energy of Cu.     

CW laser at room temperature using vitreous substances

With the aim of finding laser glasses operating in CW at room temperature, a comparative study was made of various neodymium-doped vitreous substances: silicate, borate, germanate, phosphate, and fluoride glasses. About 500 samples of phosphate glasses, doped with neodymium, were prepared and their optical properties studied. The phosphate glasses have three main advantages for laser action. 1) The fluorescence band is narrower than in silicate glasses and can be as sharp as 153 Å. 2) The optical pumping is more efficient in phosphate glasses. 3) The lifetime of the 4F3/2level is about 300 μs. The phosphate glasses have very interesting laser characteristics, i.e., in pulsed operation the threshold is 1 joule. Such a rod exhibits semicontinuous operation at room temperature pumped by a krypton arc lamp; when excited in ac, the threshold is about 1 kW. It was found that the fluoride glasses have even more promising laser properties.     

Charge accumulation of quantum dots at room temperature

The accumulation of charge in InGaAs quantum dots has been measured at room temperature by the photoelectrochemical capacitance-voltage (CV) technique for the first time. A carrier per quantum dot ratio greater than four has been observed. The use of atomic force microscopy and low temperature and room temperature photoluminescence (PL) confirm the existence of quantum dots. Also, a possible excited state is indicated by room temperature PL in a sample with small quantum dots.     

室温选支一氧化碳分子激光器

一氧化碳激光器建立粒子数反转主要是依靠非谐泵浦,在相邻的振转支跃迁上,连续发射波长在5～6微米范围的激光,其中任一振转支的出现与气体温度、谐振腔耦合系数等有密切联系。在通常情况下有十几条谱线同时参与振荡,然而在实际应用上,比如作分子光谱的研究、大气污染检测、泵浦自旋喇曼反转激光器、塞曼效应的研究等需要的往往是具有一定功率水平的单一波长激光,这就需要作所谓选支一氧化碳激光器。目前一氧化碳激光器采用的一种选支办法是将色散元件如光栅或氟化钙棱镜作为构成腔的元件,在单线上获得激光振荡,并且波长可在一定的范围内调节,然而采用这种方法输出的功率和效率将明显减少到未作选支的30％。     

Quasi-CW optical bistability in InSb at room temperature

We report the first observation of quasi-steady-state optical bistability in an InSb etalon at room temperature as a result of the generation of free carriers through two photon absorption of 10 μm radiation. Nonlinear tuning of the etalon through two free spectral ranges has been achieved, with bistability observed around the two cavity resonances. Switching from a low to high transmission state has been achieved in times less than 10 ns while switching in the opposite direction occurs within 50-100 ns. The experimental results have been successfully fitted to a numerical model of the device.     

Edge photoluminescence of single-crystal silicon at room temperature

The edge photoluminescence of single-crystal silicon (c-Si) with a peak at ～1.09 eV at room temperature is observed for structures that consist of nanocrystalline silicon (nc-Si) and c-Si. The structures are obtained by pulsed-laser deposition of an nc-Si film onto a c-Si substrate. The photoluminescence signal increases as both the density of surface states at the nc-Si/c-Si boundary and the scattering of the edge emission from c-Si in the nc-Si film decreases.