Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

Engineering science >> Instrumentation
3 proposition(s).

Design, development and evaluation of sensors based on electrical methods for detecting and quantifying airborne ultrafine particles

Département des Technologies des NanoMatériaux (LITEN)

Laboratoire de Nanocaractérisation et Nanosécurité



Research field: Air quality monitoring is a real societal challenge that leads to strong expectations from the public. Currently, there is no reliable low-cost particulate matter sensors that covers a wide range of particle size. Many optical sensors are reported but respond to particles larger than 300 nm by providing their mass concentration (PM10 and PM2.5). Only few ergonomic and accurate personal monitors allow the assessment of individual exposure to manufactured nanomaterials and ultrafine particles. This is indicative of a high potential for exploitation. Description of the research topic: We propose to develop particle microsensors offering granulometric sizing over the 5-300 nm range and the chemical composition of the collected material. The purpose of this PhD thesis is to develop, assess, theoretically and experimentally, the performances of an integrated device for the detection and the quantification of particles based on ion diffusion charging. The device is aiming to sort the particles according to their electrical mobility and to collect them selectively on a substrate according to size-resolved concentric rings. Quantitative analysis of particle charging and losses will be carried out. The electrical detection using electrometers will allow quantification in real time thanks to an appropriate signal processing algorithm. Several metrics of interest will be explored such as number-based concentration, LDSA (lung-deposited surface area) concentration and mass concentration. We propose the development of a simplified system allowing the monitoring of several channels (5-20 nm, 20-100 nm, 100-300 nm) in order to propose a solution able to determine and locate sources of ultrafine particles in real time (application to urban pollution).

Numerical methods for a personalized autonomous transcutaneous gas monitoring device

Département Microtechnologies pour la Biologie et la Santé (LETI)

Laboratoire Electronique et Systèmes pour la Santé



Respiratory diseases do affect the gas exchange between blood and exhaled air, and thus the blood concentration of biomarkers. Measuring gas skin emanations of volatile blood components such as carbon dioxide allows a continuous monitoring of their concentration. The laboratory LS2P dedicated to wearable devices for healthcare is developing an innovative wristband device based on optical infrared measurement to quantify the partial pressure of transcutaneous carbon dioxide (PtCO2). The subject of this Ph. D. thesis is to study digital signal processing methods to improve the autonomy of these devices and to allow a personalized follow-up at home of the patient. This requires in particular to study a new generation of autonomous devices based on self-awareness techniques combining optical and fluidic models. Research works will address the building of a numerical model of the device and of its interaction with the human body, the development of the associated simulation software, the study of statistical signal processing methods and compress sensing algorithms. The Ph. D. candidate should be skilled in signal processing, applied mathematics or biomedical engineering.

Performance Improvement of silicon nano-gauges of MEMS sensors

Département Composants Silicium (LETI)

Laboratoire de Caractérisation et Fiabilité des Composants



The piezoresistivity of the silicon nano-gauges is the basis of many CEA-Léti's MEMS sensors: accelerometers, pressure sensors, gas sensors? and performances of these sensors are directly conditioned by the performance of the nano-gauges. As part of this thesis, the student will conduct research work to optimize the performances of nano-gauges according to the main parameters related to their technological fabrication process: SOI substrates, doping level, implantation method, geometry, release step (to suspend the nano-gauges), passivation or annealing after release... In particular, the PhD student will study the low-frequency noise of nano-gauges made on SOI substrates: he will characterize various types of nano-gauges, will seek to understand the mechanisms at the origin of the low-frequency noise in nano-gauges and will make the necessary simulations to reinforce the hypotheses explaining the electrical fluctuations within the nano-gauges. A study of the reliability of nanojauges as a function of the current density will also have to be carried out to determine the maximum usable current for the piezoresistive measurement. These studies should allow, at the end of the thesis, to propose more efficient nano-gauges, as well as their manufacturing process. The integration of this process will be studied to allow the realization of a complete sensor based on this optimized piezoresistive transduction.

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