The influence of nanocrystals on the dielectric function of porous silicon
| Autor: | R. Herino, U. Rossow, H. Münder, M. Ligeon, Hans Lüth, U. Frotscher, M. G. Berger, Wolfgang Richter |
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| Rok vydání: | 1993 |
| Předmět: |
Materials science
Silicon Condensed matter physics Phonon Analytical chemistry Physics::Optics General Physics and Astronomy chemistry.chemical_element Surfaces and Interfaces General Chemistry Condensed Matter Physics Porous silicon Surfaces Coatings and Films Condensed Matter::Materials Science symbols.namesake chemistry Nanocrystal symbols Density of states Thin film Porosity Raman spectroscopy |
| Zdroj: | Applied Surface Science. 63:57-61 |
| ISSN: | 0169-4332 |
| DOI: | 10.1016/0169-4332(93)90064-i |
| Popis: | Porous silicon films consist of a complicated network of crystals with diameters down to the nanometer range. In the smallest crystals phonons and electrons are localized. From the Raman spectra the distributions of the nanocrystal diameters are estimated. The influence of the microscopic structure on the dielectric function is studied by spectroscopic ellipsometry. The observed reduction in the height of the imaginary part of the dielectric function is related to the porosity of the layers and to the state of oxidation. A broadening and slightly changed energies of the Van Hove singularities in the joint density of states (optical gaps) are found for the porous Si layers. By performing simulations of the dielectric function for porous Si, more information about the topology of the layers is obtained. |
| Databáze: | OpenAIRE |
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