| Автор | Ewa Wäckelgård |
| Дата выпуска | 1996-06-03 |
| dc.description | The infrared reflectance from thin alumina films on metal substrates has a deep minimum for p-polarized light at oblique incidence. This originates from absorption when light couples with a longitudinal optical (LO) phonon mode with k-vector zero. The absorption band is wide for amorphous alumina and is shifted to longer wavelengths for porous oxides compared to non-porous ones. Anodic alumina, prepared in phosphoric acid, with a pore volume fraction of 0.3, has been investigated. The s- and p-polarized reflectance has been measured for selected angles of incidence between and , and the dielectric function has been determined from these measurements. The effective dielectric function has been calculated using Maxwell-Garnett effective-medium theory for a two-component anisotropic medium consisting of air-filled cylindrical pores perpendicular to the surface in an alumina matrix with optical constants of non-porous evaporated alumina. The theoretical and experimental results are in good agreement, which shows that the redshift of the LO mode absorption for p-polarized light can be explained by the presence of pores. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | The experimental dielectric function of porous anodic alumina in the infrared region; a comparison with the Maxwell-Garnett model |
| Тип | paper |
| DOI | 10.1088/0953-8984/8/23/019 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 8 |
| Первая страница | 4289 |
| Последняя страница | 4299 |
| Аффилиация | Ewa Wäckelgård; Solid State Physics, Department of Technology, Box 534, Uppsala University, S-751 21, Uppsala, Sweden |
| Выпуск | 23 |
