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Applications of TEM TEM Conventional TEM Microstructure, morphology (grain size, orientation), phase distribution and defect analysis (point defects, dislocations.

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Presentation on theme: "Applications of TEM TEM Conventional TEM Microstructure, morphology (grain size, orientation), phase distribution and defect analysis (point defects, dislocations."— Presentation transcript:

1 Applications of TEM TEM Conventional TEM Microstructure, morphology (grain size, orientation), phase distribution and defect analysis (point defects, dislocations and grain boundaries) In situ TEM Irradiation and deformation experiments Environmental cells (corrosion) Phase transformations (hot- and cold-stage, electric field) Analytical TEM (Z-contrast imaging) Chemical composition-EDS, EELS, ELNES, EXELFS, Z-contrast imaging CBED-lattice strain, thickness, charge density HRTEM Lattice imaging, structure of complex materials and atomic structure of defects (interfaces)

2 Interpretation of Images 0.5m Bent foil image A buckled region of a thin foil and bend contour occurs where the Bragg condition is locally satisfied. bend contour Dislocations loop Dislocations are readily analyzed and characterized by means of diffraction contrast.

3 High-resolution Electron Microscopy (HREM) Dislocations High-resolution Electron Microscopy(HREM) Edge dislocation

4 Bright and Dark Field Imaging BF DF Microstructure of a Pb(ZrSnTi)O 3 specimen.  direction of structural modulation.        

5 (Pb,Nb)(Zr,Sn,Ti)O 3 PNZST Thin Films 0.3m PNZST LNO Pt Top Pb-deficient pyrochlore phase Without (a) and with (b) a top PbO cover layer ab Cross Section TEM 60nm

6 X-ray Mapping 50 nm

7 Hot- and Cold-Stage TEM 20 o C 220 o C a b c d AFEFE AFE-1 AFE-2 25 o C -100 o C a and b: PbZrO 3 single crystal C and d: Pb(ZrSnTi)O 3 ceramic

8 Field-induced Microcracking in PMNPT Crystal with m-sized Domains Crack tip {011} 0.5m domain boundary 0.1m E=0 E=10kV/cm 1 st 2 nd a b c E=6.5kV/cm f=0.3Hz 20 cycles d ef E=6.5kV/cm f=0.3Hz 100 cycles domain boundary {011} Microcrack growth rate = 0.1m/cycle

9 High Resolution Z-contrast Imaging Atomic Ordering in Ba(Mg 1/3 Nb 2/3 )O 3 (STEM)  IZ2Z2 f: -52 -64 -76 -88 -100nm HREM-Phase contrast Z-contrast A: disordered B: ordered region 110 001111

10 Sub-Nanometric EDS Analysis (JEOL-2010F Field-emission TEM) MBE-grown InGaAsP/InP Multi-quantum well structure EDS spectra taken with a 5Å Probe. A.1nm InGaAsP layer B.~3nm away from interface Within InP matrix.   A B A B InGaAsP InP HREM

11 Analytical TEM/STEM EDS Detector Condenser Lens Specimen Holder Objective Lens Magnifying Lenses HAADF Detector Viewing Chamber Camera Chamber STEM Detector or EELS Electron gun

12 Electron Energy Loss Spectroscopy (EELS) EELS is a microanalytical technique that uses the characteristic spectrum of energy losses of transmitted electrons to obtain information about elemental composition, chemical bonding, and electronic structure (oxidation state). Moreover, by selecting electrons with a specific loss energy by a slit so as to image them, element distribution in specimen can be visualized (Elemental mapping). The spatial resolution is limited by the diameter of the incident illumination focused on the sample. focused beam ~1.3Å t<500Å spectrometer EELS Annular detector e - (E, E-  E) BF DF Z-contrast image

13 Atomic Bonding States Analysis by EELS Diamond,, graphite and fullerene are the matters which consists of only carbon, so that, all of these specimens have absorption peaks around 284 eV in EELS corresponding to the existence of carbon atom. From the fine structure of the absorption peak, the difference in bonding state and local electronic state can be detected. The sharp peak at absorption edge corresponds to the excitation of carbon K-shell electron (1s electron) to empty anti-bonding pi- orbital. It is not observed for diamond, because of no pi-electron in it.

14 a.HREM image of carbon nanotube. b.Carbon map at the same region. c.EELS spectrum. d.Intensity profile of carbon map Quantification of Elemental Mapping ab c d perpendicular to the tube axis. Intensity profile corresponds well to the calculated number distribution of carbon atom (solid line) based on the size and the shape of nanotube. The intensity dip at center part is corresponding to 20 carbon atoms.

15 Energy Filtered Imaging Different elements can be imaged at a nanometer scale. Cross section of microelectronic transistor. Enhanced contrast since the contrast of unfiltered images is significantly degraded by inelastic electrons.

16 Why TEM? The uniqueness of TEM is the ability to obtain full morphological, crystallographic, atomic structural and microanalytical such as chemical composition, bonding (distance and angle), electronic structure, coordination number data from the sample. TEM is the most efficient and versatile technique for the characterization of materials.

17 Limitations of TEM Sampling Interpretation of image Beam damage Specimen preparation

18 XRD, SEM, TEM and AES Studies of Nanocrystalline BaTiO 3 Thin Film 10nm AES XRD SEM TEM T ( O C) K K-dielectric constant


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