The performance of bio- and gas-sensors depends primarily on the properties of the sensing layer. This layer is based on biomolecules, 2D materials, special multilayers or thin films, as well as many other possible structures and materials that improve the sensitivity, selectivity or other crucial parameters of the sensor. The host group for the PhD work deals both with the development of the surface layers and the measurement methods. The most important aim is to use it in applications together with domestic or international partners. The candidate should join one of the running developments. Depending on the interest and capabilities of the candidate, the work can be focused on the materials science aspect, the optical metrology or the application, it can be theoretical or experimental as well. The main method of the group is the non-destructive polarization-based optical metrology that enables sub-nanometer sensitivity with high speed to follow the interface processes during the deposition of the layer, during sensing or any other changes at the interface in liquid or gas ambient. Further information: http://www.ellipsometry.hu.