Emission de photons induite par microscopie à effet tunnel sous ultravide. Etude de nanojonctions Au/MoS2

Abstract : This work presents a study of photon emission induced by scanning tunnelling microscopy in ultra high vacuum at room temperature. On metallic surfaces, the emitted photons originate from the radiative decay of plasmons localised between the tip and the sample surface and excited by electrons tunnelling inelastically in the junction.This phenomenon has been studied on gold surfaces and the influence of different tunnelling parameters (environment, tip, tunnelling current, bias voltage) has been studied. Afterwards, optical spectra have been acquired with the tip fixed at chosen positions above the surface. Variations in the photon energy distribution have been observed and attributed to the studied surface (morphology, crystallography, contamination) or to the tip (material, apex geometry).Finally, the system has been used to study metallic nano-objects consisting of gold islands grown on semiconductor surfaces (MoS2). In this case, the spectra high energy threshold gives information about the real energy injected in the junction. Throughout these threshold measurements, results show the possibility to determine electrical properties of the interface between the island and the substrate at a nanometer scale.I-V curves showing rectifying behaviour have been obtained when the island size decreases. Photon emission in the tunnelling junction of the STM appears to be a powerful technique for electrical characterisation of nano-components.
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Submitted on : Monday, January 3, 2005 - 5:55:20 PM
Last modification on : Monday, April 29, 2019 - 4:38:53 PM
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  • HAL Id : tel-00007895, version 1

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Christian Maurel. Emission de photons induite par microscopie à effet tunnel sous ultravide. Etude de nanojonctions Au/MoS2. Matière Condensée [cond-mat]. Université Paul Sabatier - Toulouse III, 2003. Français. ⟨tel-00007895⟩

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