三、CBED－会聚束衍射
CBED形成模式
会聚束衍射盘
高阶劳厄带－HOLZ线
会聚束衍射花样－HOLZ线
高阶劳厄带
HOLZ线的形成
HOLZ线指数标定
1. 常规花样 2. 小CBED花样（L=30-50cm） 3. 000 hkl盘（L=120-300cm） 4. 标定常规花样 5. 对比确定衍射盘指数
Volume 110, Issue 4,
In the first part of this work, the objectives are to assess what could be the probability distribution of the random errors made in the lattice parameter measurements from a single CBED pattern, and to give an estimate of the systematic error. In the second part, the possibility of reducing the random error by using a statistical approach for the determination of the lattice parameters from multiple patterns is considered. To carry out the study a large number of diffraction patterns were acquired. Fig. 2 shows the location of twenty diffraction patterns used in our analysis. They were obtained for alpha tilt angles between −24° and +24° from the same area of the silicon single crystal at 93 K. Particular tilt angles and the corresponding (approximate) zone axes are listed in Table 2. The table shows that no low-index zone axes (for which dynamic effects are stronger) wer
)2( 1 ni
)2
1 t2
2
si ni
1 t2
1
2
其它：晶体点群
1
2
n
萃取复型试样/STEM
Determination of lattice parameters from multiple CBED patterns: A
statistical approach Ultramicroscopy
STEM光路图
一、STEM模式
散射体积
能损谱-能谱空间分辨率比较
二、μ－衍射和纳米束衍射
μ－衍射光路图－聚焦束
μ－衍射光路图－摇摆束
上偏转 线圈
上偏转 线圈
下偏转 线圈
下偏转 线圈
检测器
检测器
衍射和纳米束衍射的特征
• 选区衍射误差－ • 衍射花样标定相同－ • 衍射斑点强度变化－孪晶和变形
前言
目的
1] 微观分析 结构 形貌 成分 位向 － 原子 电子态
2] 实验方法 阅读文献
内容
1. 分析型电镜:Scanning-Transmission Electron Microscope 2. 高分辨透射电镜Hight Resolution Transmission Electron Microscope 3. 能谱-损失谱 Electron Energy-loss Spectroscopy 4. 扫描隧道显微镜 Scanning Tunnel Microscope 5. 原子力显微镜 Atomic Force Microscope 6. 场离子显微镜 Field Ion Microscope 7. 三维原子探针 3 Dimensional Atom Probe 8. 俄歇谱仪 Auger Electron Spectroscopy 9. X射线光电子谱仪 X- ray Electron Spectroscopy 10. 背散射电子衍射[取向成像]Electron Back Scattering Diffraction 11. 正电子分析 Positron Annihilate Technology 12. 穆斯堡尔谱 Mössbauer Spectroscopy
材料分析测试方法 高分子物理近代研究方法
近刊论文
马如璋 陆家和
孟庆昌 吴杏芳
Xiao-Feng Zhang
进藤 大辅 进藤 大辅
黄新民 张俐娜
第一章 分析型电子显微镜
分析电镜
1. STEM方式 2. μ－衍射（纳米束衍射） 3. CBED－会聚束衍射 4. EDS分析－能谱分析 5. EELS分析－损失谱分析（能量过滤）
This work is devoted to the analysis of the uncertainty in lattice parameter measurements by CBED and to methods of decreasing it. The analysis of a large number of diffraction patterns acquired from a high purity silicon sample at 93 K with the CBED technique indicates the presence of both types of errors: random and systematic. The random error follows the normal distribution, and the relative standard deviation is about 3–4×10−4 for lattice parameter measurements made from one single pattern with a LaB6 TEM without energy filter. The main systematic error apparently comes from the determination of the actual voltage. Actually, it is a random error with normal distribution. It appears as a systematic error only because of the experimental protocol according to which the same actual voltage value is assigned for all patterns acquired in a session. It is shown that both random and apparent systematic errors can be reduced by a statistical approach based on multiple patterns. The accuracy is about 3–3.5×10−4 using three-pattern projects to the actual voltage determination and a precision of about 1.5–2×10−4 can be reached using a minimum of three patterns for the determination of the single “a” parameter and about 5×10−4 for the determination of the complete set of LPs for six diffraction patterns. Moreover, the use of three (or more) patterns allows also to overcome the ambiguity problem linked to the CBED study. The multiple-pattern approach has the drawback of reducing the spatial resolution due to the different tilt angles used for the acquisition of the diffraction patterns. However, for usual study, when only three patterns are necessary, the effect of the tilt, which can be relatively small, is not detrimental.
HOLZ线分裂－测量柏氏矢量
g b 0 不分裂
点阵常数测定
a0 Huvw
N u2 v2 w2
（立方系） N=1，2
Huvw G12 / 2K
会聚角的测量
会聚角的测量
r
R hkl d hkl
测量偏离矢量、消光距离
K-M线
测量偏离矢量S和消光距离
Si
i
R
dhkl2
( si ni
原理 仪器结构 应用实例——提纲 例： 三维原子探针3DAP
m/n=2eVt2/L2
参考文献：
材料物理现代研究方法 现代分析技术
透射电子显微学 电子显微分析实用方法 Transmission Electron Microscopy -Applications in Materials Science Electron Microscopy of Nanotubes 材料评价的分析电子显微方法 材料评价的高分辨电子显微方法