Post-doctoral position (18 months) in CEMES-CNRS Toulouse

“Advanced TEM and STEM-EELS/EDX study of doped semiconducting nanostructures for tunable plasmonics”

Context

Plasmonics is a growing discipline because of promising applications in key areas such as energy and health. It is based on the optical properties of noble metal nanoparticles that can focus incident light at the nanometer scale. Highly doped, semiconductor nanoparticles can also be the seat of surface plasmon resonances. In these objects, the frequency of this resonance has the advantage of being adjustable as a function of the concentration of dopants, unlike metals for which the free carrier density is constant. At usual doping concentrations (up to 1% at.), it can reach values in the Infra-Red (IR) range and approach the near-IR or even visible range for very high doping concentrations (> 10 at%). Semiconductor plasmonics is a new and growing field. Nevertheless, if the insertion of dopants into nanostructures has been demonstrated in the literature, only a small proportion of them is electrically active, i.e. able to give rise to the necessary free carriers for the generation of a surface plasmon.

This post-doctoral position is funded by the ANR project “DONNA” (Doping at the nanoscale) which started in October 2018 and will be held at CEMES-CNRS (coordinator). The goal of this project is to develop model systems and new approaches for efficient doping of semiconductor nanostructures. A first system consisting of small highly doped Si (<10 nm) nanocrystals embedded in silica will be fabricated by plasma immersion ion implantation by the industrial partner of the project. A second system involving top-down techniques consisting of 2D networks of large nanostructures of Si (> 20 nm) of different shapes (pillars, nanowires) and elaborated at LAAS-CNRS will also be studied. Surface plasmon resonance will be measured by IR spectroscopy and will serve as an optical probe to quantify dopant activation. This study will pave the way for new active, reconfigurable and less expensive plasmonics applications, which in addition makes use of less polluting materials and is compatible with silicon technology.

Job description and required competences

The post-doctoral fellow will be in charge of the Transmission Electron Microscopy observations and STEM-EELS/EDX analyses to obtain atomic maps of the dopants inside the nanostructures elaborated by the different partners of the project.

The applicant should have a PhD in physics or materials science with a strong experience in advanced Transmission Electron Microscopy and STEM-EELS/EDS techniques. A good background in the physics of nanomaterials is a prerequisite. The candidate should speak French and/or English fluently and be able to write reports and scientific papers in English. He (She) will have to work in the framework of a project involving 6 partners and thus should have abilities to organize his (her) work as well as to communicate.

The position is available on March 2019.

Contacts: Caroline Bonafos (caroline.bonafos@cemes.fr) NeO group, CEMES-CNRS et Fuccio Cristiano (cfuccio@laas.fr) MPN group, LAAS-CNRS

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