Domains of competence / Scientific interests

• Fundamental research in the field of solid state physic, semiconductors and surface physic;
• Experimental research in the field of gas sensors based on metal oxide semiconductors (MOS);
• Complex phenomenological investigations (electrical conductivity, work function, impedance spectroscopy) in controlled gas atmosphere;
• Analyse, statistics and modelling of the experimental results;

     The main objective of the group is the fundamental comprehension of the role of the morphology of the metal oxide semiconductors (MOS) nanostructures on the surface reactivity, or more exactly on the gas-sensitive proprieties.

     More specific will attempt to bring clarifications on :

• The quantitative or qualitative nature of the effect due to crystallite dimension;
       It is intended to establish the dependence of sensor-performances upon the nano- character of the MOS structure, either as a result of the increasing specific surface, either as a result of the physical proprieties induced by the decrease in the crystallite dimensions. In the first case, the increase of the surface/volume ratio due to decreasing the crystallite dimension increases the material reactivity owing to the surface phenomena as the dominant component. In the second case, the qualitative effects are taken into account, namely the quantum proprieties induced by the decrease of the crystallite dimensions under 10 nm.
• The identification of the reaction partners in MOS interaction with the molecules of the test gas;
         We aim to understand: what are the elementary steps, what is responsible for the surface reaction with the gas molecules, what is the role of the pre-adsorbed molecules, what are the changes induced by the crystallite's dimensions. This fact implies the identification of the adsorbed species, monitoring of the changes induced by gas exposure, monitoring the reaction products both on the surface and in the gas phase.
• Understanding the charge transfer mechanism associated with the surface reactions and their connection with the transducing effect, respectively with the changes of the macroscopic parameters (physical quantities);
       We aim to understand: which is the electrical effect of different components from the sensor. We are concerned with the charge transfer process between the gas and solid molecules- especially in the distinction between the localized and non-localized interactions - and the mode that the crystallite's dimensions may affect them. Also, it is interesting to establish the influence of the crystallite's dimension on the transducer effect of a charge transfer process onto changes of an electrical parameter (macroscopic) of the sensitive layer.