Chemical analysis using coincidence Doppler broadening and supporting first-principles theory: Applications to vacancy defects in compound semiconductors
| Autor: | Christian Rauch, J.-M. Mäki, Filip Tuomisto, Ilja Makkonen |
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| Rok vydání: | 2012 |
| Předmět: |
Physics
ta214 Annihilation ta114 ta221 positron annihilation spectroscopy coincidence Doppler broadening III-nitrides Condensed Matter Physics Spectral line Coincidence Electronic Optical and Magnetic Materials Positron annihilation spectroscopy symbols.namesake Positron Vacancy defect symbols Electrical and Electronic Engineering Atomic physics electron momentum density Doppler effect ta218 density functional theory Doppler broadening |
| Zdroj: | Physica B: Condensed Matter. 407:2684-2688 |
| ISSN: | 0921-4526 |
| DOI: | 10.1016/j.physb.2012.02.039 |
| Popis: | The Doppler broadening of the positron annihilation radiation contains information on the chemical environment of vacancy defects trapping positrons in solids. The measured signal can, for instance, reveal impurity atoms situated next to vacancies. As compared to integrated quantities such as the positron annihilation rate or the annihilation line shape parameters, the full Doppler spectrum measured in the coincidence mode contains much more useful information for defect identification. This information, however, is indirect and complementary understanding is needed to fully interpret the results. First-principles calculations are a valuable tool in the analysis of measured spectra. One can construct an atomic-scale model for a given candidate defect, calculate from first principles the corresponding Doppler spectrum, and directly compare results between experiment and theory. In this paper we discuss recent examples of successful combinations of coincidence Doppler broadening measurements and supporting first-principles calculations. These demonstrate the predictive power of state-of-the-art calculations and the usefulness of such an approach in the chemical analysis of vacancy defects. |
| Databáze: | OpenAIRE |
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