Reflection electron energy-loss spectroscopy and imaging for surface studies in transmission electron microscopes

1992 ◽  
Vol 20 (4) ◽  
pp. 390-405 ◽  
Author(s):  
Z. L. Wang ◽  
J. Bentley
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Surface Studies ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Electron Energy Loss

Trends in Electron Energy Loss Spectroscopy

1977 ◽  
Vol 35 ◽  
pp. 228-229
Author(s):  
C. Colliex ◽  
P. Trebbia
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Materials Science ◽  
Analytical Technique ◽  
Recent Developments ◽  
Quantitative Results ◽  
Electron Microscopes ◽  
Electron Energy Loss ◽  
Primary Electrons

The physical foundations for the use of electron energy loss spectroscopy towards analytical purposes, seem now rather well established and have been extensively discussed through recent publications. In this brief review we intend only to mention most recent developments in this field, which became available to our knowledge. We derive also some lines of discussion to define more clearly the limits of this analytical technique in materials science problems.The spectral information carried in both low ( 0<ΔE<100eV ) and high ( >100eV ) energy regions of the loss spectrum, is capable to provide quantitative results. Spectrometers have therefore been designed to work with all kinds of electron microscopes and to cover large energy ranges for the detection of inelastically scattered electrons (for instance the L-edge of molybdenum at 2500eV has been measured by van Zuylen with primary electrons of 80 kV). It is rather easy to fix a post-specimen magnetic optics on a STEM, but Crewe has recently underlined that great care should be devoted to optimize the collecting power and the energy resolution of the whole system.

Investigation of Switching Mechanism in HfO2-Based Oxide Resistive Memories by In-Situ Transmission Electron Microscopy and Electron Energy Loss Spectroscopy

2017 ◽  
Author(s):  
T. Dewolf ◽  
D. Cooper ◽  
N. Bernier ◽  
V. Delaye ◽  
A. Grenier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Hafnium Dioxide ◽  
Switching Mechanism ◽  
Transmission Electron ◽  
Electron Energy Loss

Abstract Forming and breaking a nanometer-sized conductive area are commonly accepted as the physical phenomenon involved in the switching mechanism of oxide resistive random access memories (OxRRAM). This study investigates a state-of-the-art OxRRAM device by in-situ transmission electron microscopy (TEM). Combining high spatial resolution obtained with a very small probe scanned over the area of interest of the sample and chemical analyses with electron energy loss spectroscopy, the local chemical state of the device can be compared before and after applying an electrical bias. This in-situ approach allows simultaneous TEM observation and memory cell operation. After the in-situ forming, a filamentary migration of titanium within the dielectric hafnium dioxide layer has been evidenced. This migration may be at the origin of the conductive path responsible for the low and high resistive states of the memory.

scholarly journals Data Processing for Atomic Resolution Electron Energy Loss Spectroscopy

2012 ◽  
Vol 18 (4) ◽  
pp. 667-675 ◽  
Author(s):  
Paul Cueva ◽  
Robert Hovden ◽  
Julia A. Mundy ◽  
Huolin L. Xin ◽  
David A. Muller
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Principal Component ◽  
Power Laws ◽  
Atomic Resolution ◽  
Background Error ◽  
Background Estimation ◽  
Electron Microscopes ◽  
Electron Energy Loss

AbstractThe high beam current and subangstrom resolution of aberration-corrected scanning transmission electron microscopes has enabled electron energy loss spectroscopy (EELS) mapping with atomic resolution. These spectral maps are often dose limited and spatially oversampled, leading to low counts/channel and are thus highly sensitive to errors in background estimation. However, by taking advantage of redundancy in the dataset map, one can improve background estimation and increase chemical sensitivity. We consider two such approaches—linear combination of power laws and local background averaging—that reduce background error and improve signal extraction. Principal component analysis (PCA) can also be used to analyze spectrum images, but the poor peak-to-background ratio in EELS can lead to serious artifacts if raw EELS data are PCA filtered. We identify common artifacts and discuss alternative approaches. These algorithms are implemented within the Cornell Spectrum Imager, an open source software package for spectroscopic analysis.

Electron Energy-Loss Spectroscopy (EELS) of Fe-Bearing Olivine and Laihunite (an Oxidized Olivine)

2000 ◽  
Vol 6 (S2) ◽  
pp. 208-209
Author(s):  
Huifang Xu ◽  
Pingqiu Fu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Structure Refinement ◽  
Iron Formation ◽  
Transmission Electron ◽  
Electron Energy Loss

Laihunite that has distorted olivine-type structure with ferric and ferrous irons and ordered distribution of vacancies was first discovered in a high-grade metamorphosed banded iron formation (BIF) [1, 2]. The laihunite coexisting with fayalite (Fe-olivine), magnetite, quartz, ferrosilite, garnet and hedenbergite, formed in the process of oxidation of fayalite [2, 3]. The structure refinement of 1-layer laihunite shows P21/b symmetry and ordered distribution of vacancies in half M1 sites of olivine structure [2, 3]. Early high-resolution transmission electron microscopy (HRTEM) study and HRTEM image simulation of the 1-layer laihunite verified the structure refinement [4].Specimens of weakly oxidized fayalite and laihunite containing fayalite islands collected from Xiaolaihe and Menjiagou of Liaoning Province, NE China, have been studied using selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS), and X-ray energy-dispersive spectroscopy.

Analysis of AlxGa1-xN nanowires through simulated methods of scanning transmission electron microscopy and electron energy-loss spectroscopy

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
R. Kumar ◽  
P.J. Phillips ◽  
R.F. Klie
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

AlxGa1-xN nanowires have promising applications in ultraviolet light emitting diodes (LEDs). However, these nanowires are not typical p-n junction semiconductors, but rather rely on varying concentrations of Al versus Ga to produce electron hole pairs. More information on the atomic structure is needed to better understand the properties of these nanowires. In this study, AlxGa1-xN nanowires were imaged using scanning transmission electron microscopy (STEM) and compared to computer simulated STEM images to obtain physical information on the nanowires. Electron energy-loss spectroscopy (EELS) and FEFF9 computer simulations were also performed to better understand the structural and chemical properties of the nanowires. Results from these simulations showed that changes in the chemical ordering of the nanowires were responsible for changes in intensity and resolution in the images. These intensity and resolution trends were not a result of interface effects. This will help to further characterize nanowires in the future.

Sign in / Sign up

Export Citation Format

Share Document