With more than 320 scientists, engineers, technicians, PhD students in physics, chemistry and micro-electronics, the Institut Matériaux Microélectronique Nanosciences de Provence gathers the required expertise for research and education in materials, microelectronics and nanosciences, and supports a wide range of programs including modelling, design, architecture, processes, materials and their physico-chemical properties. IM2NP is run under the joint authority of the CNRS (French National Center for Scientific Research) and two Universities : Université d’Aix-Marseille and Université de Toulon. It is also associated with two Schools of Engineering : Ecole Polytechnique Universitaire de Marseille (Polytech’ Marseille) and Institut Supérieur d’Electronique et du Numérique (ISEN).
Within the laboratory, the Microsensors and Instrumentation team develops research activities divided into three themes: Microsystems for outdoor and indoor air quality, Thermal microsystems for nuclear instrumentation, Microsystems for medical applications. These three themes are based on the expertise ranging from the study and development of sensitive layers to the realization of micro-devices on rigid or flexible substrates.
The design and implementation of these devices require the control of the materials properties, sensor and signal conditioning, and data processing. The optimization of the sensors responses, their validation in real conditions and the reliability of the systems are based on the team’s historical know-how. These activities are supported by modeling and numerical simulation work.
Subject of the thesis:
Industrial demand for gas sensors is growing rapidly in order to develop new systems for monitoring indoor and outdoor air quality, prevention of technological risks, safety and defense (robots, drones, sensors networks, connected objects, …).
Large bandgap p-type semiconductor (3.3 eV) zinc oxide (ZnO) is an interesting candidate for gas sensor applications. Recent studies have shown that it works well for gases such as O3, NO2, CO or H2S. After performing laser-ablated ZnO-based sensors, in collaboration with CINAM, we are now able to deposit thin layers of ZnO by sputtering in the laboratory. We also get characterization benches to test the sensors under a wide variety of gases (O3, NO2, CO, NH3) or vapors (ethyl alcohol, volatile organic compounds (VOCs), etc.). The student will use these equipments to deposit the ZnO layers and to test the sensors under gas.
As in the case of tungsten oxide, WO3, or copper oxides, we wish to bring results of numerical simulations at the atomic scale to better understand the mechanisms of adsorption of simple molecules on ZnO. For calculations, the student will use the SIESTA code. Based on the density functional theory (DFT) this code allows to approach larger systems and in particular the molecule-substrate system, by means of loss in the accuracy of the calculations. The simulation results will be systematically compared to the electrical responses experimentally obtained.
Planned development: first year the student will participate in the deposition of ZnO thin films and will characterize them. Simultaneously, the study of the bulk properties of ZnO will be the opportunity to take control of the code before approaching calculations on the surface, with and without point defects. During the second year, it will be necessary to characterize ZnO sensors under ozone and to carry out the simulation of the adsorption of the molecules of O3 and O2 on the surface, with and without defects. Finally, the third year, characterization and simulation will be extended to other gases (NO, NO2, CO).
The candidate will hold a master’s degree (Master 2 or MSC) at the time of application or, at the latest, at the beginning of the thesis (September 1, 2017).
Skills: programming experience (C language),
knowledge of Linux / Unix environment,
practical sense (know how to manipulate, use measuring devices…),
autonomy, initiative, curiosity, …
To receive funding, it is essential to have obtained good marks at the master / MSC.
Financing : Public : About 1700 € gross per month
Workplace: Marseille – FRANCE
Skill area: Physics – Dense mediums, materials and components – IT, Electronics
Application deadline: 7/17/2017