簡易檢索 / 詳目顯示

研究生: 馮祺凱
Feng,Chi-Kai
論文名稱: 奈米級晶體同調性電子繞射影像之研究
Study of Nano-Particle By Coherent Electron Diffraction
指導教授: 陳福榮
Chen, Fu-Rong
開執中
Kai, Ji-Jung
口試委員:
學位類別: 碩士
Master
系所名稱: 原子科學院 - 工程與系統科學系
Department of Engineering and System Science
論文出版年: 2007
畢業學年度: 95
語文別: 英文
論文頁數: 87
中文關鍵詞: 同調性繞射影像相位復原相位重建超取樣方法
外文關鍵詞: Coherent Diffrction Imaging, phase retrieval, phase reconstruction, oversampling method, Difference map method
相關次數: 點閱:2下載:0
分享至:
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報
  • 同調性繞射影像技術(CDI)提供了一個可行的途徑:針對非週期性及有限大小的獨立奈米結構,此技術可得到原子尺寸之解析度影像。其概念是:經過物體的出口波函數可以在光學上透過超取樣(oversampling)出口波的遠場繞射圖樣,以及多次重複性的演算法回復其波函數。實驗上,我們透過電子顯微鏡拍攝單獨奈米級氧化鎂顆粒(大小約24nm的立方體)的[001]方向電子繞射圖樣,透過JOEL 2010F場發射式穿透電子顯微鏡,操作在200KeV的加速電子電壓以及奈米級電子束的條件下,我們藉著動態邊界(support)的相位回復的演算法,得到與高解析電子顯微影像相吻合的回復結果。


    The coherent diffractive imaging (CDI) technique offers a promising path toward characterization of the individual non-periodic and near-periodic isolated nanostructures at the atomic resolution. In this aberration-free microscopy, the complex exit surface wave function can be recovered from the over-sampled far-field diffraction pattern using iterative algorithms. We have recorded the image and diffraction pattern of the individual MgO nano-particle with a size of about 24nm with a crystallographic orientation [001] along the incident electron beam. The FEG-TEM (JEOL 2010F) was operated at 200keV accelerating voltage in the nano-area electron diffraction regime. For the reconstruction we utilized the phase-retrieval algorithm with dynamically defined support. The result is in agreement with the TEM image of the particle.

    1 Introduction 7 1.1 Motivations 8 2 Background Theory 10 2.1 Weak-Phase Object Approximation (WPOA) 11 2.2 Electron Diffraction by the Crystalline Materials 14 2.2.1 Scattering from the Unit Cell 14 2.2.2 Single-Crystal Diffraction 15 2.2.3 Diffraction Pattern of the Small Crystal 16 2.3 Solution of the Phase Problem by the Over-Sampling Method 19 3 Iterative Algorithms for the Phase Recovery 22 3.1 Development of the Phase Recovery Technique 22 3.2 Comparison of the Iterative Algorithms 25 3.3 Phase Recovery of the Simulated Object by the Different Methods 28 4 Experimental Procedure 33 4.1 Sample Preparation 33 4.2 Transmission Electron Microscope Operations 36 4.2.1 Nano-Area Electron Diffraction 38 4.2.2 Camera Length Calibration in TEM 39 5 Results and Discussion 43 5.1 Shape Effect of the Cubic MgO Nano-Particle 43 5.2 Procedure of the Exit Wave Function Reconstruction 45 5.3 Background Subtraction and Image Processing of the Experimental Diffraction Pattern 48 5.4 Result of the Reconstructions 55 5.4.1 Reconstruction of the Shape from One Bragg Peak 55 5.4.2 Atomic-Resolution Exit Wave Reconstruction 57 5.5 Error Metric Analysis 61 6 Conclusions 65 7 Future Works 70 8 References 7

    [1] Spence J. C. H. ed. (2003) High-Resolution Electron Microscopy. Oxford University Press Inc., New York, ISBN = 0-19-850915-4.

    [2] Spence J. C. H. (1993) “On the Accurate Measurement of Structure-Factor Amplitudes and Phases by Electron Diffraction”, Acta Crystallographica Section A, 49, pp. 231-260.

    [3] Kirkland E. J. ed. (1998) Advanced Computing in Electron Microscopy. Plenum Press, New York, ISBN = 0-306-45936-1.

    [4] Bates R. H. T. and Fright W. R. (1983) “Composite two-dimensional phase reconstruction procedure”, Journal of Optical Society of America A, 73, pp. 358–365.

    [5] Miao J., Sayre D., and Chapman H. N., (1998) "Phase retrieval from the magnitude of the Fourier transforms of non-periodic objects", Journal of Optical Society of America A, 15, pp. 1662-1669.

    [6] Gerchberg R. W. and Saxton W. O., (1972) “A practical algorithm for the determination of phase from image and diffraction plane pictures”, Optik (Stuttgart), 35, pp. 237–246.

    [7] Fienup J. R., (1978) “Reconstruction of an object from the modulus of its Fourier transform”, Optics Letters, 3, pp. 27–29.

    [8] Fienup J. R., (1982) “Phase retrieval algorithms: a comparison”, Applied Optics, 21, pp. 2758–2769.

    [9] Fienup J. R., (1986) “Phase-retrieval stagnation problems and solutions”, Journal of Optical Society of America A, 11, pp. 1987-1907.

    [10] Oszlanyi G. and Suto A., (2003) “Ab initio structure solution by charge flipping”, Acta Crystallographica Section A, 60, pp. 134-141.

    [11] Oszlanyi G. and Suto A., (2004) “Ab initio structure solution by charge flipping II Use of veak reflection”, Acta Crystallographica Section A, 61, pp. 147-152.

    [12] Elser V., (2001) “Solution of the crystallographic phase problem by iterated projections”, Acta Crystallographica Section A, 59, pp. 201-209.

    [13] Elser V., (2003). “"Phase retrieval by iterated projections”, Journal of Optical Society of America A. 20, pp. 40–55.

    [14] Bauschke et al. (2002), “Phase retrieval, error reduction algorithm, and Fienup variants: a view from convex optimization”, Journal of Optical Society of America A, 19, pp. 1334-1344.

    [15] Altman I. S., (2004) “On nanoparticle surface growth: MgO nanoparticle formation during a Mg particle combustion”, Applied Physics letters, 84, pp. 5130-5132.

    [16] Hacquart R., (2005) ”Evidence for emission and transfer of energy from excited edge sites of MgO smokes by photoluminescence experiments”, Surface Science, 595, pp. 172–182.

    [17] Fukui K.-I., (1999) “Observation of a new ridge structure along steps on the MgO(100) surface by non-contact atomic force microscopy”, Surface Science, 441, pp. 529–541.

    [18] Zuo J. M., (2004) “Coherent Nano-Area Electron Diffraction”, Microscopy Research and Technique, 64, pp. 347–355

    [19] Zuo J. M., (2000) “Electron Detection Characteristics of a Slow-Scan CCD, Camera, Imaging Plates and Film, and Electron Image Restoration”, Microscopy Research and Technique, 49, pp. 245–268.

    [20] Otsu N., (1979) "A Threshold Selection Method from Gray-Level Histograms," IEEE Transactions on Systems, Man, and Cybernetics, Vol. 9, No. 1, pp. 62-66.

    [21] Wu J. S. et al., (2005) “Diffractive electron imaging of nanoparticles on a substrate”, Nature Materials, 4, pp. 912-916. (Retracted)

    [22] Wu J. S., Spence J. C. H., O’Keeffe M. and Groy T. L., (2004) “Application of a modified Oszlanyi and Suto ab initio charge-flipping algorithm to experimental data”, Acta Crystallographica Section A, 60, pp. 326-330.

    [23] Spence J. C. H., (2004) “Coherence and sampling requirements for diffractive imaging”, Ultramicroscopy, 101, pp. 149-152.

    [24] He H., (2006) “Simple constraint for phase retrieval with high efficiency”, Journal of Optical Society of America A, 23, pp. 550.

    [25] Neumann W., (1988) Interpretation of the shape of electron diffraction spots from small polyhedral crystals by means of the crystal shape amplitude. Acta Crystallographica Section A, 44, pp. 890-897.

    [26] Chapman H. N. et al., (2006) “High-resolution ab initio three-dimensional X-ray diffraction microscopy”, Journal of Optical Society of America A, 23, pp. 1179-1200.

    [27] Pfeifer M. A. et al., (2006) “Three-dimensional mapping of a deformation field inside a nanocrystal”, Nature, 442, pp. 63-66.

    [28] Dronyak Roman’s unpublished work, Department of Engineering and System Science, National Tsing Hua University.

    無法下載圖示 全文公開日期 本全文未授權公開 (校內網路)
    全文公開日期 本全文未授權公開 (校外網路)

    QR CODE