PhD subjects

4 sujets INAC

Dernière mise à jour : 25-03-2019


• Chemistry

• Materials and applications

• Solid state physics, surfaces and interfaces

 

Quantum dots based systems for visible light redox photocatalysis of reactions useful in organic synthesis

SL-DRF-19-0678

Research field : Chemistry
Location :

SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé

Conception d’architectures moléculaires et processus électroniques

Grenoble

Contact :

Vincent MAUREL

Starting date : 01-10-2019

Contact :

Vincent MAUREL

CEA - DRF/INAC/SYMMES/CAMPE

04 38 78 35 98

Thesis supervisor :

Vincent MAUREL

CEA - DRF/INAC/SYMMES/CAMPE

04 38 78 35 98

Personal web page : http://inac.cea.fr/Pisp/vincent.maurel/

In the last decade, the emergence of photoredox catalysis has revolutionized the field of synthetic organic chemistry. Catalyst design has been boosted by development of catalysts for solar energy conversion. Ruthenium and iridium coordination complexes are playing a major role in this development. Besides these homogeneous catalysts, the used of heterogenous semiconductor photoredox catalysts for synthesis is still in his infancy. We propose here a research program dedicated to the investigation of semiconductor colloidal quantum dots (QDs) as photoredox catalysts for synthetic organic chemistry. These nanocrystalline catalysts are highly attractive since they combine some of the advantages of the homogeneous catalysts, such as large extinction coefficient in the visible spectrum, and retain the ability to be removed by filtration or centrifugation. Moreover, QDs have been found to very resistant to photobleaching and their redox properties may be fine-tuned by changing their composition (CdS, CdSe, ZnO, ZnSe... ), controlling their size and modifying the ligands used to stabilize them.

This PhD thesis will be a part of a collaborative project aiming at: 1) the use of QD-photocatalysts to generate alkoxyl radicals; 2) the development of a new class of photocatalysts combining QDs and Ag nanoparticles (QD-Ag-NP).

Development of DNA-based conducting nanowires

SL-DRF-19-0746

Research field : Materials and applications
Location :

SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé

Groupe Chimie pour la Reconnaissance et l'Etudes d'Assemblages Biologiques

Grenoble

Contact :

Yoann ROUPIOZ

Didier GASPARUTTO

Starting date : 01-11-2019

Contact :

Yoann ROUPIOZ

CNRS - DRF/INAC/SyMMES/CREAB

04 38 78 98 79

Thesis supervisor :

Didier GASPARUTTO

CEA - DRF/INAC/SyMMES/CREAB

04 38 78 45 48

Personal web page : https://www.researchgate.net/profile/Didier_Gasparutto

Laboratory link : www.symmes.fr

Due to the nanometric diameter of a DNA helix (2 nm), this biological molecule appears as a promising scaffold for metallization and low-cost production of metallic nanowires. Since the very first proof-of-concept published 20 years ago, many efforts have been made to explore new routes enabling thinner DNA-based nanowires, with higher conductivity. In collaboration with another laboratory (LMGP, INP-Grenoble), we wish to design an alternative approach based on Atmospheric Pressure Spatial Atomic Layer Deposition (AP-SALD) for the metallization of DNA. Several metals will be used, with a specific emphasis on Cu and Au. Then, such nanomaterial will be functionalized, and conjugated with biomolecules to take benefit of the huge developed area of such active bio-hybrid architectures. This PhD research project thus aims at synthesizing and characterizing new materials made of tuneable and controllable conducting nanowires. A major goal will be the design of enzymatically-active surfaces, whose applications would be a great interest for the production of more powerful biofuels for instance.

Modeling of silicon two qubit gates

SL-DRF-19-0088

Research field : Solid state physics, surfaces and interfaces
Location :

Modélisation et Exploration des Matériaux

Laboratoire de Simulation Atomistique

Grenoble

Contact :

Yann Michel NIQUET

Starting date : 01-10-2019

Contact :

Yann Michel NIQUET

CEA - DRF/INAC/MEM/L_Sim

04.38.78.43.22

Thesis supervisor :

Yann Michel NIQUET

CEA - DRF/INAC/MEM/L_Sim

04.38.78.43.22

Personal web page : https://www.quantumsilicon-grenoble.eu/team/dr-yann-michel-niquet/

Laboratory link : http://inac.cea.fr/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=12

More : https://www.researchgate.net/project/Silicon-qubits

"Quantum computers" may soon be able to solve problems beyond the reach of conventional computers. Such computers no longer manipulate electrons as particles, but as waves that maintain phase relationships and can interfere. The preparation, coherent manipulation and "reading" of quantum states is extremely challenging. One promising option for making "quantum bits" (qubits) is to divert silicon MOS transistors in order to store a few electrons and manipulate their spin. The CEA Grenoble fabricates and characterizes such devices, and develops appropriate tools for their modeling. The objective of this PhD is to study the dynamics of two (or more) qubit gates by solving the time-dependent Schrödinger equation in the presence of electronic interactions in a realistic geometry (1D and 2D arrays of qubits). Our purposes are to understand the physics of the interactions between qubits, to identify the mechanisms limiting the fidelity of the elementary quantum operations (noise, phonons, ...), and to propose innovative solutions for the design of the devices as well as for the manipulation protocols. This study will be carried out in close collaboration with the experimental physics teams working on this topic at CEA and CNRS, in the frame of the European ERC Synergy project quCUBE and of the French ANR project MAQSi.

Realization of AlN nanowire-based light emitting diodes for UV C emission

SL-DRF-19-0374

Research field : Solid state physics, surfaces and interfaces
Location :

Photonique, Electronique et Ingénierie Quantiques

Laboratoire de Nano Physique des Semi-Conducteurs

Grenoble

Contact :

Bruno GAYRAL

Bruno DAUDIN

Starting date :

Contact :

Bruno GAYRAL

CEA - DSM/INAC/SP2M/NPSC

0438782673

Thesis supervisor :

Bruno DAUDIN

CEA - DRF/INAC/PHELIQS/NPSC

04 38 78 37 50

The Minamata Convention entered into force on 16 August 2017, with the purpose of progressively banning mercury use and mercury-using devices. This directly concerns mercury lamps, which are the current source of UV light for a wide range of applications in the field of UV curing, counterfeit detection, medical and instrumentation applications, air purification. Specifically concerning food and water disinfection applications, some of current applications rely on applying bactericidal substances such as chlorine to drinking water or using antibiotics which can have unwanted side effects. Also the contact of disinfectants with food is detrimental, which requires an ecologically and economically efficient alternative. This political/societal context should boost the rapidly growing market of environment friendly UV light emitting diodes (LEDs) in the 260-280 nm range and stimulate even more the active research and development activities in the field.

AlGaN materials are ideally suited for the realization of UV LEDs since they are applicable throughout the UV-B (320–280 nm) ranges and even access a large segment of the UV-C (280–200 nm) spectral range. Despite the excellent external quantum efficiency (EQE) that have been obtained for LEDs in the near UV and visible spectral range, the EQE of AlGaN-based UV LEDs with emission wavelength shorter than 365 nm is at least one order of magnitude below the best devices in the near UV and violet wavelength range. Currently the best LEDs in the UV-B and UV-C spectral ranges exhibit EQE around 10 %. A number of factors contribute to limit the efficiencies of such conventional, layer-structured nitride based UV LEDs, resulting in this overall small value. These factors include the high density of extended defects in layers, the limited efficiency of AlGaN p-type doping associated with a limited current injection and the light extraction issue.

All these limitations can be overcome to a wide extent by using nanowires (NWs). As a matter of fact, the absence of extended defects in NWs, the higher limit solubility of both Si and Mg electrical dopants, the eased light extraction intrinsically related to the large “roughness” of an ensemble of NWs make them particularly favorable to the realization of efficient LEDs.

Indeed, the CEA-INAC group in collaboration with Néel Institute has demonstrated the realization of AlN NW-based UV LEDs by taking advantage of a high p-type doping level achieved by Mg-In codoping. This pioneering work has opened the path to a new concept of UV LEDs made of AlN- and AlGaN-based NW heterostructures.



It will be the goal of this PhD subject to amplify the preliminary results already obtained, with the purpose of obtaining an optimized, pre-industrial demonstrator. The growth of the structures will be performed by plasma-assisted molecular beam epitaxy in CEA-Grenoble INAC/PHELIQS-NPSC, the electrical characterization being made in collaboration with Institut Néel. The process of the LEDs, their light emission properties characterization and efficiency measurements will be achieved in CEA-LETI DOPT, all three partners being integrated in a feedback loop to improve the optimization process.



The candidate should have a master 2 in Nanosciences or equivalent, with a marked interest in experimental physics, material growth and characterization.

 

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