Photoluminescence of 10H-SiC

2016 ◽  
Vol 858 ◽  
pp. 269-273
Author(s):  
Anne Henry ◽  
Hiroshi Yano ◽  
Tomoaki Hatayama
Keyword(s):  
Electron Microscope ◽  
Band Gap ◽  
Transmission Electron Microscope ◽  
Lower Energy ◽  
Free Exciton ◽  
Binding Energies ◽  
Photoluminescence Spectra ◽  
Transmission Electron ◽  
First Time

The photoluminescence of the near band gap emission of 10H-SiC is revealed for the first time and detected just below 3.0 eV. The crystallinity thus polytype of the sample is controlled with transmission electron microscope analyses and Laue diffraction. On the photoluminescence spectra up to eight sharp lines are associated to the non-phonon lines of the nitrogen bound exciton even if ten are expected in 10H-SiC. Phonon replicas of these non-phonon lines are observed at lower energy with energy separations similar than those in other hexagonal SiC polytypes. At moderate temperature free-exciton replicas are also observed which allow the determination of the excitonic band gap at 3020.6 meV, value in agreement with the hexagonality of 10H-SiC of 40%. The binding energies associated to the nitrogen bound-excitons are determined as well as the ionization energies of the nitrogen donors in the 10H-SiC polytype.

scholarly journals Meso-Scale Transmission Electron Microscope Tomography Applied for Wax Distribution in Toner Particles

2013 ◽  
Vol 19 (S5) ◽  
pp. 58-61 ◽  
Author(s):  
Mino Yang ◽  
Jun-Ho Lee ◽  
Hee-Goo Kim ◽  
Euna Kim ◽  
Young-Nam Kwon ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Three Dimensional ◽  
Chromatic Aberration ◽  
Laser Printer ◽  
Medium Voltage ◽  
Transmission Electron ◽  
Z Contrast ◽  
Contrast Image

AbstractDistribution of wax in laser printer toner was observed using an ultra-high-voltage (UHV) and a medium-voltage transmission electron microscope (TEM). As the radius of the wax spans a hundred to greater than a thousand nanometers, its three-dimensional recognition via TEM requires large depth of focus (DOF) for a volumetric specimen. A tomogram with a series of the captured images would allow the determination of their spatial distribution. In this study, bright-field (BF) images acquired with UHV-TEM at a high tilt angle prevented the construction of the tomogram. Conversely, the Z-contrast images acquired by the medium-voltage TEM produced a successful tomogram. The spatial resolution for both is discussed, illustrating that the image degradation was primarily caused by beam divergence of the Z-contrast image and the combination of DOF and chromatic aberration of the BF image from the UHV-TEM.

Electron Diffraction Analysis and Determination of Se Phase Formed by Reduction of Oxoselenium Anions by Iron (II) Hydroxide

1997 ◽  
Vol 3 (S2) ◽  
pp. 755-756
Author(s):  
D. C. Dufner ◽  
R. A. Zingaro ◽  
A. P. Murphy ◽  
C. D. Moody
Keyword(s):  
Aqueous Solution ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Transmission Electron Microscope ◽  
Iron Hydroxide ◽  
Distilled Water ◽  
Electron Diffraction Analysis ◽  
Transmission Electron ◽  
Standard Solution

Since the early 1980s, Se toxicity in wildlife has created a great deal of interest and concern. Reservoirs, marshes, and wetlands in which excessive amounts of Se have been found are considered to be the source of their toxicity problems. Thus, an effective and inexpensive treatment of Se-contaminated waters which significantly lowers the concentration of this element is needed. One such method for removing selenites and selenates from water utilizes iron (II) hydroxide as a reducing agent. In this work, the reduction products are analyzed in the transmission electron microscope (TEM) using electron diffraction and energy-dispersive spectroscopy (EDS) to determine the presence of Se.A “standard” aqueous solution was prepared by the addition of KOH to distilled water to pH 8.8. Sufficient quantities of Na2SeO3 or Na2SeO4 were weighed and dissolved in the “standard” solution to yield SeO3-2 or SeO4-2 ions. A weighed quantity of Fe(NH4)2(SO4)2 was then added to the SeO3-2 or SeO4-2 “standard” solution to form a precipitate of iron hydroxide.

Routine Determination of X-Ray Detector Efficiencies Using Submicron Spheres of Pure Materials

1985 ◽  
Vol 43 ◽  
pp. 416-417
Author(s):  
Thomas F. Kelly
Keyword(s):  
Electron Microscope ◽  
Energy Range ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Characteristic Line ◽  
X Rays ◽  
Detector Efficiency ◽  
X Ray ◽  
Transmission Electron

The purpose of this paper is to outline an approach to routine determination of x-ray detector efficiencies over the entire applicable energy range that may be used on any transmission electron microscope.BACKGROUNDThe quantification of x-ray intensities using the ratio technique can be accomplished [see, for example, 1] using a relation of the form:Here, for element A, CA is the composition in the sample as a weight fraction, kA is the x-ray generation constant (see below) which contains only sample-dependent information, eA is the detector efficiency for characteristic x-rays which contains only detector-dependent information, and lA is the measured x-ray intensity in a characteristic line.

A new method for determining the normals to planar structures and their trace directions in transmission electron microscopy

1994 ◽  
Vol 27 (5) ◽  
pp. 762-766 ◽  
Author(s):  
Q. Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
New Method ◽  
Planar Structures ◽  
Transmission Electron

With aid of a transmission-electron-microscope (TEM) double-tilt holder, a method for determining the normals to planar structures and their traces in a TEM is developed. This method is considered to be simple and convenient when compared with other methods. The accuracy of the method for the determination of both the normals to planar structures and their traces is within 2°.

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