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Offers : 25

Strain driven Group IV photonic devices: applications to light emission and detection

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Start date : 02/01/2023

offer n° 20222608

Straining the cristal lattice of a semiconductor is a very powerfull tool enabling controlling many properties such as its emission wavelength, its mobility…Making strain amplification microstructures is a rather recent technique allowing accumulating very significant amounts of strain in a micronic constriction, such as a microbridge (up to 4.9% for Ge [1]), which deeply drives the electronic properties of the starting semiconductor. Nevertheless, the architectures of GeSn microlasers under strong deformation and recently demonstrated at the SiNaPS laboratory in the IRIG institute [2] cannot afford modulating on demand the applied strain within the very same device, the latter being frozen “by design”. The target of this 18 months post doc is to fabricate photonic devices of the MOEMS family (Micro-opto-electromechanical systems) allowing combining the local strain amplification in the semiconductor and actuation features via an external stimulus, with the objectives to go towards: 1-a wide band and tunable laser microsource via external command and 2-new types of photodetectors, both in a Group IV technology (Si, Ge and Ge1-xSnx). This work is part of a wider collaboration between the IRIG and LETI institutes concerning the study of Si compatible Group IV laser sources and will be based at the SiNaPS laboratory of the IRIG institute. A strong interaction with the LETI partners is expected (collaboration around the growth and material aspects).

The candidate will have to fabricate the devices at the Plateforme Technologique Amont (PTA) and to carry out the optics and material characterizations. A PhD in the field of semiconductors physics or photonics, as well as strong skills in micro-nanofabrication are required.

[1] A. Gassenq et al, Appl. Phys. Lett.108, 241902 (2016)
[2] J. Chrétien et al, ACS Photonics2019, 6, 10, 2462–2469.


The CEA IRIG (Institut de Recherche Interdisciplinaire de Grenoble) is located at Grenoble and belongs to the CEA DRF (Fundamental Research Division). The SINAPS laboratory at IRIG/PHELIQS ( investigates the new physical phenomena appearing when group IV semiconductors are down-sized to the nanometer scale. SiNaPS research ranges from material growth and nanofabrication to physical study of nanostructure structural, electronic and optical properties.

Starting January 2023
Contact / Supervisor : Nicolas Pauc, CEA-IRIG-PHELIQS,

Place of work : CEA Grenoble


  • Keywords : Condensed matter physics, chemistry & nanosciences, Engineering sciences, Electronics and microelectronics - Optoelectronics, Emerging materials and processes for nanotechnologies and microelectronics, Optics - Laser optics - Applied optics, Photonics, Imaging and displays, Solid state physics, surfaces and interfaces, IRIG, PHELIQS
  • Laboratory : IRIG / PHELIQS
  • CEA code : 20222608
  • Contact :

Theoretical and experimental studies of the polarized light’s propagation into OLED structure

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Start date : 01/12/2021

offer n° PsD-DRT-22-0018

In collaboration with chemists from CEA Saclay and the University of Rennes, Leti’s LCEM laboratory is interested in new chiral molecules for OLED (Organic Light Emitting Device) sources able to emit circularly polarized light (CP). The interest of these CPOLED sources is multiple and encompasses both micro-screens and healthcare applications. While the state of the art is quite extensive on the chemical part, few studies have looked at the generation and transport of light in CPOLEDs components.Likewise, the conditions for measuring the polarity of the light emitted are not very detailed in the existing literature.

At the LCEM laboratory, where these chiral molecules are integrated into CPOLED devices, the goal is to design OLED architectures that can better preserve the polarization of light. To do this, it is essential to understand the propagation of light in OLED stacks from a theoretical and experimental point of view. This work is part of a larger collaboration set up in the ANR “i-chiralight” project.

In this context, we are proposing a study which will take place in two phases.

– Study of simple emitting materials: The materials to be studied will be thin layers deposited under vacuum using evaporation’s system of thin layers available in the laboratory. The organic materials used will be supplied by our chemical partners in Saclay or Rennes. Optical characterizations such as ellipsometry,photoluminescence, etc. will be carried out in order to assess the performance of molecules in terms of emission efficiency but also in terms of the rotational power of light. For this last point, a model able to calculate all the terms of the Müller matrices is under development and the validation of this one will be a work to be carried out by the post-doctoral fellow.

– Study of complete OLED components: In the second phase of this work, we will focus on the complete OLED system by studying the propagation of optical modes in the stack of the different layers const

  • Keywords : Défis technologiques, Sciences pour l'ingénieur, Photonique, imageurs et écrans, DOPT, Leti
  • Laboratory : DOPT / Leti
  • CEA code : PsD-DRT-22-0018
  • Contact :

Evaluation of RF system power consumption for joint system-technology optimization

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Start date : 01/05/2021

offer n° PsD-DRT-21-0081

To be able to increase and optimize wireless transmission systems based on a hybridization of technologies, it is strategic to be able to quickly evaluate the capabilities of these technologies and to adapt the associated architecture as best as possible. To this end, it is necessary to implement new approaches to global power management and optimization.

The work of this post-doctoral contract is at this level.

The first step will be to develop some new power consumption models of the RF transceivers building blocks (LNA, Mixer, Filter, PA, …). A modelization approach has already been tested and validated in the group. In the next step, it will be needed to link the performances of the overall wireless system to the building blocks characteristics. Lastly, the optimization will be applied thanks to an efficient solution. Lastly, the proposed approach will be validated in the optimisation of a multi-antenna millimeter wave wireless system. An evaluation methodology specific to 3D will also be put in place

  • Keywords : Défis technologiques, Sciences pour l'ingénieur, Electronique et microélectronique - Optoélectronique, Réseaux de communication, internet des objets, radiofréquences et antennes, DSYS, Leti
  • Laboratory : DSYS / Leti
  • CEA code : PsD-DRT-21-0081
  • Contact :

Optomechanical resonators for (bio)particle mass sensing in biomedical applications

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Start date : 01/04/2022

offer n° PsD-DRT-22-0051


Nano-Electro-Mechanical systems (NEMS) generate particular interest in a wide range of applications, from quantum measurements to biotechnology. The goal of the project is to characterize biological particles in mass ranges currently unachievable by conventional techniques with possible applications in disease diagnosis, air quality control and characterization of novel therapeutic agents.

Thanks to LETI’s prime technological means and NEMS expertise, major technological milestones have been achieved (Sage et al. Nature Commun. 2015; Sansa et al. Nature Nanotechnol. 2016). In parallel with these efforts, LETI has been developing optomechanics as a high-performance transduction method, allowing ultra-sensitive detection of NEMS resonators with applications in mass spectrometry (Sansa et al. Nature Commun. 2020).

The EDyP team of the Interdisciplinary Research Institute in Grenoble (IRIG) has extensive expertise in high-end mass spectrometry instrumentation and its use to achieve protein identification and quantification. LETI and IRIG initiated a joint effort towards developing a new generation of NEMS based mass spectrometer, which led to the first measurement of viral particles above 100 MDa using nanomechanical resonators (Dominguez-Medina et al. Science 2018).


The objective of the post-doc is to develop the next generation of NEMS mass spectrometer for biological detection using optomechanical resonator arrays. The hired person will integrate the MEMS team in LETI, where he/she will characterize optomechanical resonators already available. Then, she/he will work in close collaboration with the IRIG team to adapt the current mass spectrometry set-up at IRIG to the new sensors, and to perform mass spectrometry measurements.

  • Keywords : Défis technologiques, Sciences pour l'ingénieur, Technologies pour la santé et l’environnement, dispositifs médicaux, DCOS, Leti
  • Laboratory : DCOS / Leti
  • CEA code : PsD-DRT-22-0051
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Developement of relaxed pseudo-substrate based on InGaN porosified by electrochemical anodisation

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Start date : 01/03/2021

offer n° PsD-DRT-21-0035

As part of the Carnot PIRLE project starting in early 2021, we are looking for a candidate for a post-doctoral position of 24 months (12 months renewable) with a specialty in material science. The project consists in developing a relaxed pseudo-substrate based on III-N materials for µLEDs applications, especially for emission in red wavelength. The work will focus on developing an InGaN-based epitaxy MOCVD growth process, on an innovative substrate based on electrochemically anodized and relaxed materials. He (She) will have characterize both the level of relaxation of the re-epitaxied layer and its crystalline quality. These two points will promote the epitaxial regrowth of an effective red LED. The candidate will be part of the team, working on the PIRLE project, will be associated to the work on red LED growth and its optical and electro-optical characterizations.

  • Keywords : Défis technologiques, Physique de l'état condensé, chimie et nanosciences, Matériaux et procédés émergents pour les nanotechnologies et la microélectronique, Physique du solide, surfaces et interfaces, DPFT, Leti
  • Laboratory : DPFT / Leti
  • CEA code : PsD-DRT-21-0035
  • Contact :
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