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Reference : UMR6072-SOPRAS-004
Workplace : CAEN
Date of publication : Friday, April 30, 2021
Scientific Responsible name : GUILLET Bruno
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 September 2021
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
Development of innovative radiation detectors
based on functional oxides for applications in IR and THz ranges
We are particularly interested in the composition La0.7Sr0.3MnO3 (LSMO), which exhibits a strong variation of electrical
resistance as a function of the temperature around 300 K, as well as a low electrical noise, for the realization of
uncooled radiation sensors such as bolometers . The targeted areas of use are space missions dedicated to earth
monitoring, and meteorology. They could be extended to applications in various fields such as security, medical or
Currently, in order to achieve the ultimate performance in the millimeter band, submillimetric to far-infrared, all
receivers use superconducting material-based detectors whose low critical temperature (superconducting transition
temperature) requires cooling powers that are often incompatible with long-term space missions. Our preliminary
results obtained with LSMO suspended structures are very interesting because Noise Equivalent Power (NEP) of the
order of 1 pWHz-1/2 was obtained at 300 K [2-5]. Under optimized temperature and current conditions, bolometer noise
measurements show that they can be phonon noise limited, very close to the theoretical limits for thermal detectors at
300 K. Optical characterizations (visible at 655 nm and IR 3.39 μm using a HeNe laser) made in our laboratory have
confirmed that we can manufacture sensitive IR uncooled bolometers based on suspended LSMO thin films. Finally,
recent preliminary measurements carried out at the SOLEIL synchrotron demonstrated that LSMO bolometers are
sensitive in different wavelength ranges ([8μm-12μm], [1μm-20μm], [16μm-1000μm]) even if they were not coupled to
an antenna .
It is therefore interesting to continue at first the optimization of suspended bolometers based on LSMO thin films for
detection in the near / medium infrared and THz. Then, the objective is to work on the coupling radiation - detectors in
order to adapt the detectors to the ranges of wavelength where it lacks performant uncooled detectors. Indeed, LSMO
bolometers coupled to adapted integrated planar antennas should in particular be able to meet the detection needs in the
THz and far infrared range where there are no efficient uncooled solutions. This work will be done within a national
project ANR called BOLOTERA (2021-2024) which involves two others partners in Lille: a lab named IEMN (UMR
8520) and a start-up company named VMicro. Several missions in Lille are planned during the thesis within this
consortium. New measurement campaigns at the SOLEIL synchrotron are also planned to refine the results.
The recruited phD researcher will work on the development of innovative radiation detectors based on functional oxides for applications in IR and THz ranges. She/He will take part to the design, the fabrication in clean room, the electrical and optical characterization and the implementation of the detectors.
a) Evaluation of potential performance, design and manufacture of clean room components (thin film structuring coupled to broadband planar micro
b) Electrical and optical characterization, modeling of the physical phenomena appearing in the devices. Measurements in the THz frequency range will complete the knowledge on the optical properties of ultra-thin LSMO far-infrared layers.
c) Implementation of the detector: in this final step, a detector system will be designed and implemented in the framework of collaborations.- Static electrical measurements
Master diploma or equivalent diploma. For this strong multidisciplinary
subject, profiles based on/or merging competencies of electronics,
sensors, physics, material physics and / or micro-technology clean room
will be considered with a great attention. The proposed thesis is for
curious, inventive, dynamic candidates having a strong scientific
background and a sense of collaborative works. Experience of research
and experimentation will be appreciated extra points.
The GREYC Laboratory is a research laboratory located in Caen, Normandy
(France). It carries out research activities in the field of digital
sciences covering several aspects of computer science including image
processing, data mining, artificial intelligence, computer security,
mathematical computing, automatic language processing, electronics and
instrumentation. The GREYC electronics team designs and studies
high-sensitivity sensors up to the physical limits that are linked to
fluctuations, from their development in thin layers of innovative
materials to applications. The quantities measured include the magnetic
field, electric field, temperature, radiation, or gas detection. The
team's measurement engineering skills are adapted to academic,
industrial or cultural issues.
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