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Reference : UMR8635-JULBAR-001
Workplace : VERSAILLES
Date of publication : Thursday, January 07, 2021
Type of Contract : FTC Scientist
Contract Period : 18 months
Expected date of employment : 1 March 2021
Proportion of work : Full time
Remuneration : Starting from 2600 € gross per month (depending on experience)
Desired level of education : PhD
Experience required : Indifferent
The discovery of two-dimensional materials in 2004 opened up promising opportunities in many areas (electronics, mechanics, thermics, spintronics). Recently, research has naturally turned to the realization of heterostructures integrating these 2D materials, with the promise of further enriching their possibilities: a significant improvement of atomic layer performances when embedded in heterostructures has already been demonstrated. The optical and electronic properties of these structures are still to be discovered. A large variety of excitons types in these stacks begins to be unveiled (interplane excitons, interface excitons, moiré, etc.) with promising features for optoelectronics (excitronics).
The young researcher will investigate the optoelectronic properties of the layers and structures studied in the laboratory, analysing the influence of the many degrees of freedom available in the design of heterostructures (choice of materials, number of atomic layers stacked, orientation of layers between atomic planes, etc.). He.she will develop the diagnostics that will allow the proper integration of these 2D materials into devices, based on the instrumental expertise of GEMaC.
The 2D materials will be analysed as bulk crystals (hBN, black phosphorus,…), atomic layers obtained by exfoliation or synthesized directly on substrate, and stacked in heterostructures (e.g.: hBN/MoSe2/hBN, hBN/ black phosphorus/hBN, graphene/hBN/graphene, …).
The candidate will combine different spectroscopy techniques. The study of excitonic properties will be based on the cathodoluminescence system developed in the laboratory. The analyses will be carried out at room temperature or at low temperature (liquid helium), in continuous or pulsed excitation. The dynamics of luminescence processes can be evaluated today, using the fast electron blanker recently developed at the laboratory (temporal resolution 100 ps). The quality of the crystals, number of atomic layers and their crystallographic orientation will be studied in Raman scattering, with a system accessing ultra-low frequencies (< 100 cm-1) and analysis in polarization.
The young researcher will interact closely with the researchers, engineers and PhD students of the laboratory and as well with its partner laboratories. He.She will analyse the experiments carried out by correlating the optical results to the sample geometries measured in AFM, to the structural measurements made in transmission microscopy and confronting them with theoretical calculations of 2D excitons. He.She will follow sample characterizations and report them to partners of ANR and European projects. He.She will have at heart the valorization of the results through the writing of scientific articles and oral communications in international conferences.
Holding a PhD is necessary. Good knowledge in semiconductor physics and optical spectroscopy is essential. Experience in electron microscopy, digital processing and data analysis (images, datacubes, spectra) will be appreciated.
A significant experience in handling or studying 2D materials is a plus.
A good knowledge of English is expected both orally and in writing, especially for scientific papers and reports in collaborative projects.
The activities of the Condensed Matter Study Group (GEMaC, http://www.gemac.uvsq.fr) are based on a common expertise in physics and material sciences in the fields of wide bandgap semiconductors, nanoscale optics, functional oxides and switchable molecular materials.
The young researcher will join the DIAM (Diamond for Electronics) team where the 2D materials have long been studied using the tools initially developed for diamond spectroscopy. The team's pioneering works dates back to 2006 on hBN and nanotubes. Since then, the team has acquired recognized expertise on the optical properties of these emerging materials.
The postdoctoral fellow will report to Julien Barjon. He.She will work at GEMaC in Versailles, in close collaboration with Ingrid Stenger and Christophe Arnold. He.She will be involved in the many collaborations of the team: at the local level with the LEM-ONERA in Chatillon, with the partners of the ANR EPOS-BP and the European Flagship project on Graphene.
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