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Offers : 31

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

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Start date : 01/01/2023

offer n° PsD-DRF-23-0020

Straining the crystal lattice of a semiconductor is a very powerful tool enabling controlling many properties such as its emission wavelength, its mobility…Modulating and controlling the strain in a reversible fashion and in the multi% range is a forefront challenge. Strain amplification 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 in the IRIG institute [2] cannot afford modulating on demand the applied strain and thus the emission wavelength 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) 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 wavelength tunable laser microsource and 2-new types of photodetectors, both in a Group IV technology (Si, Ge and Ge1-xSnx). The candidate will conduct several tasks at the crossroads between fabrication and optoelectronic characterization:

a-simulation of the mechanical operation of the expected devices using FEM softwares, and calculation of the electronic states of the strained semiconductor

b-fabrication of devices at the Plateforme Technologique Amont (lithography, dry etching, metallization, bonding), based on results of a

c-optical and material characterization of the fabricated devices (PL, photocurrent, microRaman, SEM…) at IRIG-PHELIQS and LETI.

A PhD in the field of semiconductors physics or photonics, as well as skills in microfabrication are required.

[1] A. Gassenq et al, Appl. Phys. Lett.108, 241902 (2016)

[2] J. Chrétien et al, ACS Photonics2019, 6, 10, 2462–2469

  • Keywords : Condensed matter physics, chemistry & nanosciences, Technological challenges, Emerging materials and processes for nanotechnologies and microelectronics, Solid state physics, surfaces and interfaces, IRIG, PHELIQS
  • Laboratory : IRIG / PHELIQS
  • CEA code : PsD-DRF-23-0020
  • Contact : nicolas.pauc@cea.fr

Neural signal decoding for clinical Brain Spine neuroprosthesis

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Start date : 01/10/2022

offer n° PsD-DRT-22-0132

The postdoctoral project will be carried out at CEA/LETI/CLINATEC, in collaboration with EPFL (Lausanne, Switzerland) within the frame of multidisciplinary Brain-Machine Interface program. The program goal is to explore novel solutions for functional rehabilitation and/or compensation for people with sever motor disabilities using neuroprosthetics. Neuroprosthetics record, and decode brain neuronal signal for activating effectors (e.g. implantable spinal cord stimulator) directly without physiological neural control command pass way interrupted by spinal cord injury. A set of decoding algorithms analyzing the neuronal activity recorded at the level of the cerebral cortex were developed at CLINATEC. They were tested in the frame of clinical research protocols for tetraplegia in Grenoble and for paraplegia in Lausanne. The postdoctoral fellow will contribute to the next highly ambitious scientific breakthroughs addressing the medical needs of patents. Using the revolutionary technology (EPFL) of cervical stimulation for the upper limb control in tetraplegics, the postdoctoral project will aim at the upper limb BMI control algorithms performing real life tasks. The innovative decoding algorithms will be developed for controlling different effectors and combinations including Cartesian control and the direct joints control. Hidden semi-Markov Model will be employed to take into account the action temporal sequences performing real-life tasks. The decoder(s) will be tested in related clinical trial.

  • Keywords : Engineering sciences, Technological challenges, Health and environment technologies, medical devices, Mathematics - Numerical analysis - Simulation, Clinatec (LETI), Leti
  • Laboratory : Clinatec (LETI) / Leti
  • CEA code : PsD-DRT-22-0132
  • Contact : tetiana.aksenova@cea.fr

Advanced biological functionalization for graphene biological sensors on flexible subtrate

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Start date : 01/07/2022

offer n° PsD-DRT-22-0139

The need for biological sensing solutions is constantly growing. Amid targeted applications, some require biosensor with high sensitivity. At CEA LETI we are running a project that aim at developing novel innovative wound dressing equipped with graphene biological sensors to track wound bacterial proliferation indicative of sepsis. The sensor is a Solution gated graphene FET-like sensor. In the Framework of that project, we develop and test innovative biological functionalization strategy adapted to the graphene sensors. This functionalization protocol, once established and tested through several reference instruments will be implemented on the sensor. The impact of the biological functionalization on the final sensing performance will be studied.

  • Keywords : Engineering sciences, Technological challenges, Health and environment technologies, medical devices, Materials and applications, DCOS, Leti
  • Laboratory : DCOS / Leti
  • CEA code : PsD-DRT-22-0139
  • Contact : thomas.alava@cea.fr

Development of large area substrates for power electronics

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Start date : 01/05/2022

offer n° PsD-DRT-22-0111

Improving the performance of power electronics components is a major challenge for reducing our energy consumption. Diamond appears as the ultimate candidate for power electronics. However, the small dimensions and the price of the substrates are obstacles to the use of this material. The main objective of the work is to overcome these two difficulties by slicing the samples into thin layers by SmartCut™ and by tiling these thin layers to obtain substrates compatible with microelectronics.

For this, various experiments will be carried out in a clean room. Firstly, the SmartCut™ process must be made more reliable. Characterizations such as optical microscopy, AFM, SEM, Raman, XPS, electrical, etc. will be carried out in order to better understand the mechanisms involved in this process.

The candidate might be required to work on other wide-gap materials studied in the laboratory such as GaN and SiC, which will allow him to have a broader view of substrates for power electronics.

  • Keywords : Engineering sciences, Technological challenges, Emerging materials and processes for nanotechnologies and microelectronics, Materials and applications, DCOS, Leti
  • Laboratory : DCOS / Leti
  • CEA code : PsD-DRT-22-0111
  • Contact : lucie.levan-jodin@cea.fr

Catalytic properties at the nanoscale probed by time-resolved Bragg coherent diffraction imaging

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Start date : 01/03/2022

offer n° PsD-DRF-22-0087

The postdoctoral research project is part of a five-year ERC-funded project called CARINE (Coherent diffrAction foR a Look Inside NanostructurEs towards atomic resolution: catalysis and interfaces – https://carine-erc.eu) to develop and apply new coherent diffraction imaging (CDI) capabilities. The main objective of the project is to image nanostructures in situ during reaction and to reveal their structure evolution in time and at the nanoscale to probe bulk, surface and interface effects, as well as defects. Catalysts play a key role in approximatively 90% of industrial chemical processes. The development of heterogeneous catalysis with selectivity targeting the 100% is a constant challenge as well as understanding the durability and ageing of the catalyst itself. However, the catalytic process and the associated structural changes still remain poorly understood. Understanding how catalyst structure is affected by the adsorbed layer under reaction conditions is therefore of utmost importance to formulate catalyst structure-performance relations that guide the design of better catalysts.

  • Keywords : IRIG, MEM
  • Laboratory : IRIG / MEM
  • CEA code : PsD-DRF-22-0087
  • Contact : mrichard@esrf.fr
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