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Etude des propriétés électriques et optiques d'hétérostructures Si/CaF2 déposées sur des substrats de Si(111)

Abstract : This work deals with the electrical and optical properties of various Si/CaF2 heterostructures grown by molecular beam epitaxy. This technique of growth allows us to fabricate very thin CaF2 layers and more complex structures such as photoluminescent multilayers as well as Fabry-Perot structures.
In the first part, we have investigated the electrical properties of thin CaF2 layers either monocristallines or nanocristallines deposited on Si(111) substrates of different thicknesses by varying the growth parameters, in particular the substrate temperature. This study demonstrates the importance of the preparation of the Si substrate to get high quality CaF2 layers. In particular, a template layer of Si permits to get CaF2 layers exempt of pin-holes. Furthermore, this study shows that the interface is of B-type (rotation of 180° with respect to the [111] direction) for CaF2 layers deposited at high temperature while it is of A-type when the layers are deposited at low temperature. This type (A or B) determines the density of electrical traps present at the interface. Time-resolved electrical measurements evidence that long relaxation times of charge carriers are at the origin of hysteresis phenomena observed on I-V characteristics as well as the behavior of negative differential resistance. These dynamic effects have been modelled by means of an equivalent lumped-element circuit.
In the second part, we were interested in the fabrication and characterization of interference filters (Bragg mirrors, microcavities) in order, on one hand to tune the emission wavelength, and on the other hand to narrow the spectral bandwidth of the photoluminescence of nanometric Si/CaF2 multilayers. Reflectivity measurements show that it is possible to get Bragg mirrors having a high reflectivity in a large spectral domain even for a small number of periods and to get Fabry-Perot structures having a well defined mode of a few tens of nanometers in the visible.
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Contributor : Guillaume Guirleo <>
Submitted on : Tuesday, January 6, 2004 - 5:22:07 PM
Last modification on : Thursday, March 5, 2020 - 6:58:55 PM
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  • HAL Id : tel-00002652, version 2



Guillaume Guirleo. Etude des propriétés électriques et optiques d'hétérostructures Si/CaF2 déposées sur des substrats de Si(111). Matière Condensée [cond-mat]. Université de la Méditerranée - Aix-Marseille II, 2002. Français. ⟨tel-00002652v2⟩



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