Current status of carbon‐related defect luminescence in GaN

A new tool for characterizing extended defects in Silicon Carbide (SiC) based on photoluminescence imaging is presented. In contrast to other techniques like Defect Selective Etching (DSE) or X-ray topography this technique is both fast and non-destructive. It is shown that several defect types, especially those relevant for the performance of electronic devices on SiC (i.e. Stacking Faults and Basal Plane Dislocations) can be investigated. The tool is therefore usable in research and development for a quick feedback on process related defect generation as well as in a production environment for quality control.

Download Full-text

Current status of special planetary and lunar theories and ephemerides

Symposium - International Astronomical Union ◽

10.1017/s007418090010556x ◽

1966 ◽

Vol 25 ◽

pp. 266-267

Author(s):

R. L. Duncombe

Keyword(s):

Observational Data ◽

Current Status ◽

Numerical Errors

An examination of some specialized lunar and planetary ephemerides has revealed inconsistencies in the adopted planetary masses, the presence of non-gravitational terms, and some outright numerical errors. They should be considered of temporary usefulness only, subject to subsequent amendment as required for the interpretation of observational data.

Download Full-text

Current Status of Electron Microscopic Cytochemistry

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100093262 ◽

1972 ◽

Vol 30 ◽

pp. 2-3

Author(s):

Kazuo Ogawa

Keyword(s):

Current Status ◽

Electron Microscopic ◽

Electron Microscopic Cytochemistry

Download Full-text

Current Status of Solid-State X-Ray Systems

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100117789 ◽

1985 ◽

Vol 43 ◽

pp. 158-161

Author(s):

Martin Peckerar ◽

Anastasios Tousimis

Keyword(s):

Solid State ◽

Electric Fields ◽

Spectral Lines ◽

Current Status ◽

Mobile Charge ◽

Electron Hole ◽

X Ray ◽

Sensing Systems ◽

Transmission Electron ◽

Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

Download Full-text

Flux-pinning-related defect structures in melt-processed YBa2Cu3O7-x

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100150514 ◽

1993 ◽

Vol 51 ◽

pp. 936-937

Author(s):

Z. L. Wang ◽

R. Kontra ◽

A. Goyal ◽

D. M. Kroeger ◽

L.F. Allard

Keyword(s):

Volume Fraction ◽

Local Density ◽

Stacking Faults ◽

Image Resolution ◽

Defect Structures ◽

Atomic Structures ◽

Transmission Electron ◽

Point Image ◽

Related Defect ◽

Point To Point

Previous studies of Y2BaCuO5/YBa2Cu3O7-δ(Y211/Y123) interfaces in melt-processed and quench-melt-growth processed YBa2Cu3O7-δ using high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS) have revealed a high local density of stacking faults in Y123, near the Y211/Y123 interfaces. Calculations made using simple energy considerations suggested that these stacking faults may act as effective flux-pinners and may explain the observations of increased Jc with increasing volume fraction of Y211. The present paper is intended to determine the atomic structures of the observed defects. HRTEM imaging was performed using a Philips CM30 (300 kV) TEM with a point-to-point image resolution of 2.3 Å. Nano-probe EDS analysis was performed using a Philips EM400 TEM/STEM (100 kV) equipped with a field emission gun (FEG), which generated an electron probe of less than 20 Å in diameter.Stacking faults produced by excess single Cu-O layers: Figure 1 shows a HRTEM image of a Y123 film viewed along [100] (or [010]).

Download Full-text

Electron-deficient boron-based catalysts for C–H bond functionalisation

Chemical Society Reviews ◽

10.1039/d0cs00380h ◽

2021 ◽

Author(s):

Yuanhong Ma ◽

Shao-Jie Lou ◽

Zhaomin Hou

Keyword(s):

Review Article ◽

Current Status ◽

Comprehensive Overview

This review article provides a comprehensive overview to recognise the current status of electron-deficient boron-based catalysis in C–H functionalisations.

Download Full-text