Quantitative Scanning Transmission Electron Microscopy for the Measurement of Thicknesses and Volumes of Individual Nanoparticles

2009 ◽  
Vol 1184 ◽  
Author(s):  
Helge Heinrich ◽  
Biao Yuan ◽  
Haritha Nukala ◽  
Bo Yao
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Cross Sections ◽  
Scanning Transmission Electron Microscopy ◽  
Sample Thickness ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Individual Nanoparticles

AbstractIn Scanning Transmission Electron Microscopy (STEM) the High-Angle Annular Dark-Field (HAADF) signal increases with atomic number and sample thickness, while dynamic scattering effects and sample orientation have little influence on the contrast. The sensitivity of the HAADF detector for a FEI F30 transmission electron microscope has been calibrated. Additionally, a nearly linear relationship of the HAADF signal with the incident electron current is confirmed. Cross sections of multilayered samples for contrast calibration were obtained by focused ion-beam (FIB) preparation. These cross sections contained several layers with known composition. A database with several pure elements and compounds has been compiled, containing experimental data on the fraction of electrons scattered onto the HAADF detector for each nanometer of sample thickness. Contrast simulations are based on the multi-slice formalism and confirm the differences in HAADF-scattering contrast for the elements and compounds. TEM offers high lateral resolution, but contains little or no information on the thickness of samples. Thickness maps in energy-filtered transmission electron microscopy, convergent-beam electron diffraction and tilt series are so far the only methods to determine thicknesses of particles in a transmission electron microscope. We show that the calibrated HAADF contrast can be used to determine the thicknesses of individual nanoparticles deposited on carbon films. With this information the volumes of nanoparticles with known composition were determined.

Electron Tomography of HEK293T Cells Using Scanning Electron Microscope–Based Scanning Transmission Electron Microscopy

2012 ◽  
Vol 18 (5) ◽  
pp. 1037-1042 ◽  
Author(s):  
Yun-Wen You ◽  
Hsun-Yun Chang ◽  
Hua-Yang Liao ◽  
Wei-Lun Kao ◽  
Guo-Ji Yen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Scanning Transmission Electron Microscopy ◽  
Electron Tomography ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
3D Volume ◽  
Scanning Electron

AbstractBased on a scanning electron microscope operated at 30 kV with a homemade specimen holder and a multiangle solid-state detector behind the sample, low-kV scanning transmission electron microscopy (STEM) is presented with subsequent electron tomography for three-dimensional (3D) volume structure. Because of the low acceleration voltage, the stronger electron-atom scattering leads to a stronger contrast in the resulting image than standard TEM, especially for light elements. Furthermore, the low-kV STEM yields less radiation damage to the specimen, hence the structure can be preserved. In this work, two-dimensional STEM images of a 1-μm-thick cell section with projection angles between ±50° were collected, and the 3D volume structure was reconstructed using the simultaneous iterative reconstructive technique algorithm with the TomoJ plugin for ImageJ, which are both public domain software. Furthermore, the cross-sectional structure was obtained with the Volume Viewer plugin in ImageJ. Although the tilting angle is constrained and limits the resulting structural resolution, slicing the reconstructed volume generated the depth profile of the thick specimen with sufficient resolution to examine cellular uptake of Au nanoparticles, and the final position of these nanoparticles inside the cell was imaged.

Sample Thickness Determination by Scanning Transmission Electron Microscopy at Low Electron Energies

2013 ◽  
Vol 20 (1) ◽  
pp. 111-123 ◽  
Author(s):  
Tobias Volkenandt ◽  
Erich Müller ◽  
Dagmar Gerthsen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Primary Electron ◽  
Sample Thickness ◽  
Simulated Image ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Wide Range ◽  
Scanning Transmission

AbstractSample thickness is a decisive parameter for any quantification of image information and composition in transmission electron microscopy. In this context, we present a method to determine the local sample thickness by scanning transmission electron microscopy at primary energies below 30 keV. The image intensity is measured with respect to the intensity of the incident electron beam and can be directly compared with Monte Carlo simulations. Screened Rutherford and Mott scattering cross-sections are evaluated with respect to fitting experimental data with simulated image intensities as a function of the atomic number of the sample material and primary electron energy. The presented method is tested for sample materials covering a wide range of atomic numbers Z, that is, fluorenyl hexa-peri-hexabenzocoronene (Z = 3.5), carbon (Z = 6), silicon (Z = 14), gallium nitride (Z = 19), and tungsten (Z = 74). Investigations were conducted for two primary energies (15 and 30 keV) and a sample thickness range between 50 and 400 nm.

scholarly journals Unhindered Brownian Motion of Individual Nanoparticles in Liquid-Phase Scanning Transmission Electron Microscopy

Nano Letters ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 7108-7115 ◽  
Author(s):  
Murat Nulati Yesibolati ◽  
Kim I. Mortensen ◽  
Hongyu Sun ◽  
Anders Brostrøm ◽  
Sofie Tidemand-Lichtenberg ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Brownian Motion ◽  
Liquid Phase ◽  
Scanning Transmission Electron Microscopy ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Individual Nanoparticles

scholarly journals High Dynamic Range Pixel Array Detector for Scanning Transmission Electron Microscopy

2016 ◽  
Vol 22 (1) ◽  
pp. 237-249 ◽  
Author(s):  
Mark W. Tate ◽  
Prafull Purohit ◽  
Darol Chamberlain ◽  
Kayla X. Nguyen ◽  
Robert Hovden ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Transmission Electron Microscopy ◽  
Dynamic Range ◽  
Array Detector ◽  
Transmission Electron ◽  
Pixel Array ◽  
Scanning Transmission ◽  
Pixel Array Detector

AbstractWe describe a hybrid pixel array detector (electron microscope pixel array detector, or EMPAD) adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy. The 128×128 pixel detector consists of a 500µm thick silicon diode array bump-bonded pixel-by-pixel to an application-specific integrated circuit. The in-pixel circuitry provides a 1,000,000:1 dynamic range within a single frame, allowing the direct electron beam to be imaged while still maintaining single electron sensitivity. A 1.1 kHz framing rate enables rapid data collection and minimizes sample drift distortions while scanning. By capturing the entire unsaturated diffraction pattern in scanning mode, one can simultaneously capture bright field, dark field, and phase contrast information, as well as being able to analyze the full scattering distribution, allowing true center of mass imaging. The scattering is recorded on an absolute scale, so that information such as local sample thickness can be directly determined. This paper describes the detector architecture, data acquisition system, and preliminary results from experiments with 80–200 keV electron beams.

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