Thèse 2023 : Porous Titanium Nitride material for microelectrode based biosensing

Context :

1. In biosensing for environment or health applications, microelectrode flexible sensors are
still very challenging depending on the application target. Several designs are commonly
used (either single electrodes or InterDigitated Electrodes), requiring different interface
solutions (resistive or capacitive impedance leading to potentiometric or amperometric
outputs). The challenges are the sensitivity and selectivity, stability and life time,
compatibility with heterogeneous and aggressive environment (in case of biological
tissues or polluted water/soils in agrifood). TiN which is bio-compatible, has shown
promising properties in case of well controlled surface porosity obtained with specific
etching [S. Paul Shylendra, et al, ―Titanium Nitride Thin Film Based Low-Redox-
Interference Potentiometric pH Sensing Electrodes,‖ Sensors, vol. 21,(1), 2020 ; M. Liu,
et al, ―A titanium nitride nanotube array for potentiometric sensing of pH,‖ The Analyst,
vol. 141, (5), 2016 N. Sun et al., Sputtered titanium nitride films with finely tailored
surface activity and porosity for high performance on-chip micro-supercapacitors, Journal
of Power Sources 489 (2021) 229406].

2. The thesis in proposed in continuity with a previous phD work (Thuy Nguyen,
defense in 2023) on flexible smart sensors dedicated to healthcare, and in relation with
expertise developed on TiN material within the ERC Neurodiam of L Rousseau. A first
proof of concept has been demonstrated on the interest of TiN material for pH sensor
electrodes [Porous Titanium Nitride Electrodes on Miniaturised pH Sensor for Foetal
Health Monitoring Application, T. Nguyen, B. Journet, H. Takhedmit, G. Lissorgues,
DTIP2022]. But deep material characterization is required to understand the
sensitivity/accuracy improvement in regard to the porosity control in case of porous TiN
versus flat TiN. And the bibliography on this material is showing an increasing
interest on several domains: optics, thermo-optics, electronics [. M. Reed, M. R.
Ferdinandus, N. Kinsey, C. DeVault, U. Guler, V. M. Shalaev, A. Boltasseva, and A. Urbas,
« Transient Nonlinear Refraction Measurements of Titanium Nitride Thin Films, » in
Conference on Lasers and Electro-Optics, OSA Technical Digest (online) (Optica
Publishing Group, 2016), paper FTu1A.6; A. Calzolari and A. Catellani, « Controlling the
TiN Electrode Work Function at the Atomistic Level: A First Principles Investigation, » in
IEEE Access, vol. 8, pp. 156308-156313, 2020, doi: 10.1109/ACCESS.2020.3017726.]. In
addition, we have the clean room facilities in ESYCOM allowing working on the
optimization process for porous TiN.

Thesis topic :

1. As explained in the context above, there is an increasing interest in the TiN material
which was initially only used for thin film coatings. The first target application is pH
measurement because the induced porosity of etched TiN, presenting a specific columnar
structure, will accelerate H+ ions migration and interaction with the surface at the
electrode/electrolyte interface and increase the sensitivity. Other applications can be
explored outside electrochemical sensors, in neurosciences for new microelectrode arrays
[Ryynänen, T., et al. « Ion beam assisted E-beam deposited TiN microelectrodes – applied
to neuronal cell culture medium evaluation.‖, Front. Neurosci. 12:882. 2018.], or
in energy storage though supercapacitor concepts [Grigoras, K., et al. ―Conformal
titanium nitride in a porous silicon matrix: a nanomaterial for in-chip supercapacitors.‖,
Nano Energy 26, 340–345, 2016]. If thermo-optic properties appear to be original (to be
checked in this thesis), it will also extend the interest of porous TiN towards
metamaterial applications.

2. The project will be to develop new TiN samples with controlled porosity and to
implement such a material on microelectrodes for sensing performance assessment.
The solution can be easily transferred on flexible substrates based on Esycom previous
experience on soft implants. An option will be to add the wireless transmission to
these sensors for remote monitoring, considering a resonant RFID like circuit [P.
Marsh et al., « Flexible Iridium Oxide Based pH Sensor Integrated With Inductively
Coupled Wireless Transmission System for Wearable Applications, » in IEEE Sensors
Journal, vol. 20, no. 10, pp. 5130-5138, 15 May15, 2020, doi:
10.1109/JSEN.2020.2970926; M. Smalley, K. Anderson and N. McFarlane, « Towards a
Wireless pH-Impedance Sensor System for IoT Applications, » 2022 IEEE 65th
International Midwest Symposium on Circuits and Systems (MWSCAS), Fukuoka, Japan,
2022, pp. 1-4, doi: 10.1109/MWSCAS54063.2022.9859313]. Several applications can
be chosen for the final demonstration: healthcare pH blood/sweat/urine monitoring; pH
acidity levels in food; pH monitoring in polluted soils or water… depending on the
existing collaborations.

3. Expected publications in IEEE Sensors or IEEE J. of Microelectromechanical Systems and
patent.

Expected planned work :

The work will be divided into several parts corresponding to the main issues :
– Material sample fabrication (optimization process for the porosity control) and full
characterization (electrical, optical, chemical composition, electrochemical, thermal…) –
mainly Year 1
– Material integration into a biosensing unit (based on existing know-how) – half of Year 2
– Implementation of the biosensor with a wireless transmission module – half of Year 2
– Sensor characterization to demonstrate its functionality and performances – Year 3
– Writing the manuscript & journal paper – half of Year 3

Curriculum :

The phD candidate should have a multidisciplinary background with special focus on :
Material sciences, applied physics, micro-technology and electronics.
A personal interest in biosensors will be appreciated.

Contact :

Supervision : Pr Gaëlle LISSORGUES
Email : gaelle.lissorgues@esiee.fr

Le laboratoire ESYCOM s’inscrit dans les domaines de l’ingénierie des systèmes de communication, des
capteurs et des microsystèmes pour la ville, l’environnement et la personne.
Les thèmes abordés sont plus spécifiquement :
– les antennes et propagation en milieux complexes, les composants photoniques – micro-ondes ;
– les microsystèmes pour l’analyse de l’environnement et la dépollution, pour la santé et l’interface avec le
vivant ;
– les micro-dispositifs de récupération d’énergie ambiante mécanique, thermique ou électromagnétique.

Thèse 2023 : Electromagnetic signature of autonomous sensors based on the dielectric breakdown of air using triboelectric generators

Study context :

The powering of self-powered distributed sensors requires either the use of batteries that need to be renewed
regularly or the harvesting and storage of energy over a long period of time, which does not allow real-time
sensing. This thesis proposes to study a new type of self-powered wireless sensor including instantaneous wireless
transmission thanks to the combined action of the triboelectric effect and the electrostatic breakdown of air.

This thesis will take place at ESYCOM lab which has more than 15 years of history in electrostatic kinetic energy
harvesting with a recent focus on triboelectricity, and more than 20 years of history in antenna design. In a recent
work, switches based on electrostatic discharged has been used in conditioning electronic for managing the high
voltages in triboelectric kinetic energy harvesters [Zhan20].

Objective of the thesis :

Triboelectric energy generators are electrostatic transducers which are self-polarized when two suitable materials
are brought into contact [Zha18]. They have the particularity of allowing the generation of voltages of several
hundred volts, sometimes in a single mechanical actuation. This high voltage, if applied to the terminals of a
« switch » consisting of two conductors separated by a gap of a few microns, can be the cause of the « breakdown »
of the ambient dielectric (here the air) if the limits of the Paschen law are reached. Consequently, an
electromagnetic wave is generated by this micro-plasma according to the principle of the Hertz experiment
[Jou89].

Converting mechanical energy into electromagnetic waves while encoding a data in the transmitted signal will
allow to free the transmitter system from any electronics except for a few diodes and capacitors, which will greatly
reduce the overall power consumption. Although it has been demonstrated that such a transmission system with a
triboelectric energy generator with a surface area of less than one cm2 can emit an electrical pulse that can be
sensed at a distance of more than ten meters [Wang21], the exact mode of transmission and the means of
influencing its characteristics are still largely misunderstood.

In this thesis, we propose to study in a first step how to maximize the propagation distance by introducing an
antenna at the emission which is excited by the generated electric spark. In a second step, the candidate will
define the best approach to modulate the emitted signal to transmit information. One possibility would be to add a
capacitive sensor in the transmission loop to make the frequency modulation dependent on other mechanical
parameters to be measured. Another option is to modulate the emitted spark by controlling the gap between the
switch electrodes. This could be achieved by using a MEMS plasma switch [Zha20] with a moving electrode
controlled by the capacitive sensor.

Candidate profile :

Applicants should have followed a MSc degree related to electronics, microwaves and photonics or
applied physics. Skills in optoelectronics and integrated components are beneficial. Experience and
knowledge on CAD software, Maltlab, C/C++ programming language, Electromagnetic software will be
strongly appreciated.

Contacts and application :

Send a CV and a cover letter to:
Jean-Marc Laheurte : jean-marc.laheurte@univ-eiffel.fr
Philippe Basset : philippe.basset@univ-eiffel.fr
Armine Karami : armine.karami@univ-eiffel.fr

ESYCOM short description :

ESYCOM Lab has a strong expertise in communication systems, sensors and MEMS (micro electromechanical
systems). This expertise matches the labs project entitled Communication systems and
sensors for the city, the environment and people . Six research areas are developed: antennas and
propagation, architectures, microwave photonic devices, microsystem analysis, medical sensors, energy
harvesting. Three well-equipped platforms are dedicated to the characterization of the developed
components and systems. ESYCOM Lab is labeled CNRS.

Thèse 2023 : Statistical Approaches for Surrounded Antennas

Context :

The recent growth of Internet of Things (IoT) has brought a variety of services and applications in our everyday life. The advent of 5G communications cellular systems and beyond with an increased data rate, a reduced end-to-end latency and an improved coverage is considered to be a major driver for the development of a truly global IoT. The various nature of the connected objects can be highlighted through different new areas of application. For example, IoT offers a wireless low-cost high-density distributed sensor-based tool for Structural Health Monitoring (SHM) which can replace a regular maintenance into a more cost-effective condition-based one. In a completely different context, Wearable Health Monitoring Systems (WHMS) deploy various types of miniature wearable or implantable sensors to improve the supervision of patients. Besides these specific applications, IoT can bring solutions to the recent public health problems by providing individuals with reliable information. For example, nowadays a public issue concerns the food quality and traceability. Another example is the integration of sensors (or small cells base stations) in the urban infrastructure.

Despite the diversity of the cited applications, some common aspects can be recognised regarding the conditions under which the communicating sensors or terminals operate:
– A partial or uncertain knowledge of the close environment
– Intrinsic variability of the sensor or terminal support.

Given the complexity and variability of the environment or of the device itself, a purely deterministic approach to model antennas and their interactions with their immediate environment would not be realistic. In this context, the assessment of antennas performance must be revisited through a statistical and parsimonious modelling approach using efficient surrogate models (substitution or metamodels).

This PhD proposal aims to develop and establish on a solid basis a statistical methodology to address the issues of surrounded antennas. The ambition is to pave the way to handle such issues in an applicative context, with a potential industrial impacts. Different domains such as textile antennas, wearables, “soft electronics”, IoT, RFIDs, etc. are of concern.

PhD proposal :

The use of Uncertainty Quantification (UQ) techniques for the robust design of engineering systems has gained tremendous interest over the last decade. Based on a computational model of a system, UQ first consists in representing the variability of the input parameters by an appropriate probabilistic model. The sensitivity analysis aims at determining which input parameters play the most significant role in terms of output uncertainty. All uncertainty quantification techniques rely upon repeated runs of the simulator based on different values of the input parameters.

The well-known Monte Carlo simulation technique, which uses a large number of random samples of input parameters is not affordable in practice when complex simulators (such as EM softwares) are used. Surrogate modelling techniques such as polynomial chaos expansions (PCE) [1], Kriging [2], low-rank tensor representation [3] and neural networks [4] have been developed to bypass this computational issue.

In the domain of antenna design and optimisation, advanced statistical techniques and surrogate modelling have proved to be useful by taking into account important degrees of freedom and numerous fabrication constraints. The examples go from the design of UWB patch antennas [5] or deformable textile antennas [6] to the design of antenna arrays [7].

In this proposal, “surrounded antennas” refer to configurations in which antennas with given intrinsic parameters are perturbed by their close environment (other radiating elements, nearby scatterers, support objects, human body, etc.) The characterisation of surrounded antennas (body centric wireless network, antennas on complex platforms, RFID tags, etc.) is still a real challenge. The literature based on statistical approaches for this category of antennas remains still limited and relies mainly on conventional techniques, such as the Monte Carlo method [8], [9]. Moreover, to our knowledge these statistical techniques have not been used to analyse the performances of global system observables (key performance indicators) at the system level.

With respect to the state of the art, the objectives of this PhD thesis are:
– To develop an appropriate and robust surrogate model for surrounded antennas in an uncertain or partially known environment;
– To assess the antenna and the whole system performances statically using the obtained antenna metamodel.

Work plan :

Build “antennas” metamodel: A number of pertinent input parameters are identified and their variations are modelled using appropriate probability density functions depending either on the design, usage, close environment, application and fabrication of the antenna. Using the appropriate statistical techniques, an accurate surrogate model for the “variable” antenna is introduced.
Statistically assess “antennas” performance: The substitution model of the variable antenna is used to quantify the impact of the variability of the input parameters over the outputs of the antenna. The quantities of interest for the antenna (such as return loss, gain, etc.) calculated from the outputs of the substitution model are called antenna’s output indicators.
Statistically assess “system” performances: The substitution model of the variable antenna is integrated in a higher level system simulator. The impact of the variability of the global system parameters, along with the local variability of the antenna itself, over the system outputs is quantified. The quantities of interest for the system output (such as read-range in an RFID system, BER for a data communication system, etc.) are called Key Performance Indicators (KPIs).

Applicant profile :

This PhD offer is intended for the candidates having a Master’s degree in « 3EA » or an equivalent degree in « Electrical engineering ». The following conditions are required:
– Solid knowledge in electromagnetics and applied mathematics
– Interest for experimentation
– Autonomy in computer programming

Contact :

Supervisor (Directeur): Jean-Marc Laheurte, Professor, ESYCOM/UGE
Advisors (Encadrants): Beoit Poussot, Associate Professor, ESYCOM/UGE
Shermila Mostarshedi, Associate Professor, ESYCOM/UGE
The application file should include CV, statement of purpose, recommendation letters and all academic transcripts and may be addressed by email to Shermila Mostarshedi (Shermila.Mostarshedi@univ-eiffel.fr) and Benoit Poussot (benoit.poussot@univ-eiffel.fr).

ESYCOM laboratory :

The ESYCOM laboratory is within the field of communication systems, sensors and microsystems for the city, the environment and the person.
The topics of interest are more specifically:
– antennas and propagation in complex media, photonic-microwaves components;
– microsystems for environmental analysis and pollution control, for health and the interface with living organisms;
– micro-devices for ambient mechanical, thermal or electromagnetic energy harvesting.

Thèse 2023 : Méta-matériaux en silicium aléatoirement structuré pour la gestion et la conversion de rayonnement thermique

Directrice : Elodie Richalot ; Encadrant.e.s : Maha Ben Rhouma, Armande Hervé, Elyes Nefzaoui

Nous nous intéresserons dans le cadre de cette thèse à une catégorie particulière de méta-matériaux à base de silicium aléatoirement micro et nano-structuré, à savoir le Black Silicon (BSi), étudié au laboratoire depuis une quinzaine d’années.
Contrôler finement la gamme spectrale de forte émissivité de ce matériau (BSi) en fonction de l’application (TPV ou refroidissement radiatif) est le principal objectif de cette thèse. Cela passera par des simulations électromagnétiques, la fabrication d’échantillons et leur caractérisation à température ambiante et haute température.
Dans un premier temps, il s’agira d’explorer et de simuler numériquement différentes configurations pouvant répondre aux problématiques et à la sélectivité désirée, en considérant notamment l’association de différentes méta-matériaux : multi-couches, réseaux de surface, association de différents matériaux possédant des propriétés spectrales intéressantes du type Black Silicon/Graphène ainsi que différentes combinaisons des catégories précédentes afin d’ajuster leur propriétés radiatives (émissivité, réflectivité).
Les résultats obtenus sur le Black Silicon pendant les thèses de Sreyash Sarkar (soutenue en décembre 2022) et de Lan Gao (soutenue en février 2023) seront un point de départ et d’appui pour cette nouvelle thèse. La première portait sur les propriétés radiatives du Black Silicium dans l’infrarouge alors que la seconde s’est focalisée sur son utilisation pour la récupération d’énergie solaire. Des développements supplémentaires sont indispensables pour l’adapter à des applications telles que le refroidissement radiatif ou encore la conversion thermo-photovoltaïque.

Ces simulations/modélisations se feront en se basant sur les équations de Maxwell qui rendent parfaitement compte de la physique en jeu dans les différents dispositifs visés dans la thèse. Nous utiliserons dans un premier temps les méthodes dites « modales » telles que la FMM (Fourier Modal Method) et la FMM-ASR (FMM équipée du concept « Adaptive Spatial Resolution ») [12,13,14], pour lesquelles l’équipe encadrante possède déjà une expertise [15]. Ces méthodes sont reconnues comme les outils numériques les plus efficaces et performants pour modéliser des nano-structures périodiques lamellaires qui composent souvent les métamatériaux. Pour modéliser des réseaux présentant une géométrie relativement complexe (non lamellaire), ces méthodes peuvent être exploitées en procédant à un découpage en tranches de la structure, c’est la « staircase approximation ». Une autre piste intéressante est d’utiliser la méthode dite « de Chandezon » (Methode-C) qui consiste à résoudre les équations de Maxwell dans un système de coordonnées adaptées à la surface diffractante. Son intérêt réside dans l’écriture simple et naturelle des conditions aux limites.
Dans le cas des structures sub-longueur d’onde, des modèles théoriques approchés peuvent être développés en utilisant la méthode des milieux effectifs couplée à l’utilisation de la méthode de la matrice de transfert (matrice T) ou de diffusion (matrice S) en adaptant la « staircase approximation » ; cette approche a déjà été développée et utilisée au sein de l’équipe [7]. Ces modèles peuvent être complétés par des simulations basées sur la méthode des éléments finis pour tenir compte plus précisément du caractère désordonné de la structuration des matériaux considérés [16].

Les métamatériaux à fort potentiel pourront ensuite être optimisés par l’utilisation de techniques d’apprentissage automatique (réseaux de neurones artificiels, apprentissage par renforcement, etc.) en fonction de l’application visée couplées aux méthodes de calcul électromagnétiques mentionnées ci-dessus.
Les meilleures structures candidates seront ensuite fabriquées dans les salles blanches de ESIEE Paris en s’appuyant sur l’expertise accumulée sur le sujet depuis une quinzaine d’années. Leurs propriétés radiatives seront caractérisées sur le banc de spectroscopie et microscopie infrarouge à transformée de Fourier (FTIR) récemment développé au sein des plateformes de caractérisation en micro-énergie du laboratoire basées à ESIEE Paris. Des développements sont en cours pour étendre ces moyens de caractérisation au-delà de la température ambiante vers les hautes températures. Ces développements nouveaux permettront de caractériser les métamatériaux étudiés à haute température ce qui est particulièrement pertinent pour des applications de récupération d’énergie thermique telles que le TPV.

Cette thèse bénéficiera de collaborations déjà établies du laboratoire ESYCOM avec d’autres laboratoires en France (Institut Pprime de Poitiers) ou des collaborations naissantes (CEMHTI à Orléans), notamment sur la caractérisation à haute température des propriétés électromagnétiques (permittivité diélectrique) des matériaux micro et nano-structurés. Elle permettra également de renforcer les contributions du laboratoire à l’activité de la communauté nationale des nanomatériaux pour l’énergie à travers le GDR NAME (NAnoMaterials for Energy) et du groupe projet CNRS TREE (Thermal Radiation to Electric Energy conversion). Le doctorant bénéficiera par conséquent d’un environnement dynamique avec de nombreuses possibilités de collaboration.

Voir le sujet complet dans le PDF joint

Contact : Elodie Richalot, directrice de thèse – elodie.richalot-taisne@univ-eiffel.fr