Investigation of the space charge regime of epitaxially grown GaAs (100) by high-resolution electron energy-loss spectroscopy
| Autor: | Juergen A. Schaefer, V.M. Polyakov, A. Elbe, J. Wu, G. J. Lapeyre |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Free electron model
Condensed matter physics Chemistry Surface plasmon General Physics and Astronomy High resolution electron energy loss spectroscopy Surfaces and Interfaces General Chemistry Electron Condensed Matter Physics Drude model Space charge Surfaces Coatings and Films Condensed Matter::Materials Science Condensed Matter::Strongly Correlated Electrons Plasmon Molecular beam epitaxy |
| Zdroj: | Applied Surface Science. :24-34 |
| ISSN: | 0169-4332 |
| DOI: | 10.1016/s0169-4332(96)00116-x |
| Popis: | High-resolution electron energy-loss spectroscopy (HREELS) has been used in situ to investigate the space charge regime of homogeneously doped and delta-doped (Si) GaAs (100) samples, which were grown by molecular beam epitaxy (MBE). The simplest model we applied to fit the experimental energy-loss spectra of homogeneously doped samples is based on a step-like distribution of free electrons with the Drude dielectric response function. In this case, the spatial dispersion of plasmon excitations is neglected, whereas in the Thomas-Fermi (or Debye-Huckel) model it is considered. The results of the fitting carried out show that the Drude model gives the higher values for both the free-electron density and the plasmon damping when compared to the Thomas-Fermi model. It thus appeared to provide a more adequate description of the collective dynamic response of free electrons. Post-annealing of the homogeneously doped GaAs (100) samples reveals a significant reduction (compensation) of the free-electron density due to the localization of free electrons on defects diffused from the surface to the bulk. |
| Databáze: | OpenAIRE |
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