Responsable : Olivier Pluchery
Contact : olivier.pluchery@insp.jussieu.fr - 01 44 27 94 10
Tutelle : CNRS - Sorbonne Université
Mots clés : Stage M2
Gratification : Oui
Page des stages de(s) l'équipe(s) : Physico-chimie et dynamique des surfaces  
Description du stage

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Keywords: gold nanoparticles, plasmonics, nanoelectronics, Atomic Force Microscopy

Scientific description:

Due to their plasmonic properties, gold nanoparticles behave as nano-antenna that concentrate the local electromagnetic field to nanometer scale dimensions [1]. The localized surface plasmon resonance (LSPR) occurs in gold nanoparticles and generate strong oscillations of the free electrons. In certain conditions some of these electrons can be expelled out of the nanoparticles and injected into a semiconductor. This corresponds to the recent field of research of the “hot electron physics”. One key point for a successful injection of electrons or holes is the existence of a strong built-in potential at the junction between the nanoparticle and the surface.

In our group we develop an approach based on advanced Atomic Force Microscopy (AFM) techniques such as conductive AFM or KPFM (Kelvin Probe Force Microscopy) to investigate this topic. Recently, we have demonstrated that we can measure the Schottky barrier at the interface between a gold nanoparticle and a doped semiconductor (Fig. 1) [2]. Moreover, we have also developed an optical microscope to measure dark field optical hyperspectral images of single nanoparticles and correlate the plasmonic properties with the KPFM images (Fig. 2) [3].

The present internship will focus on understanding how to measure with accuracy the local electric field at the nanoparticle-semiconductor interface, using a KPFM. The candidate will learn how to use KPFM, how to interpret the data, and will compare them with existing electrical models. During the internship, the measure of the plasmonic response of these nanostructures will also be carried out using the dark field optical hyperspectral microscope. The final goal is to prove that the electron injection can be triggered with on optical beam and measured with KPFM.

[1] Pluchery, O. & Bryche, J.-F. An Introduction to plasmonics.  (World Scientific, 2023).

[2] Lechaptois, L., Prado, Y. & Pluchery, O. KPFM visualisation of the Schottky barrier at the interface between gold nanoparticles and silicon. Nanoscale 15, 7510-7516 (2023).

[3] Abadie, C., Liu, M., Prado, Y. & Pluchery, O. Hyperspectral dark-field optical microscopy correlated to atomic force microscopy for the analysis of single plasmonic nanoparticles: tutorial. J. Opt. Soc. Am. B 41, 1678 (2024)

Techniques/methods in use: Atomic Force Microscopy, dark field optical microscopy

Applicant skills: skills for experiment, dedication and passion for understanding experimental results

Possibility for a Doctoral thesis: YES. Funding through Doctoral School ED397, after selection