Field of scientific interest
The Laboratory of Electron Spectroscopy of Solid Surfaces (LESSS) is the successor of material assets and scientific traditions of two laboratories (Laboratory of mass spectrometry and Laboratory of physical chemistry of solid surfaces), created in the 70s of last century.
The scientific topic of LESSS is the experimental studies (with the methods of electron spectroscopy-XPS, HREELS, LEED) of the surface layers of solids, which are widely used in catalysis, corrosion, microelectronics, material sciences and others application areas of the modern life. The importance of studying surface properties stems from the fact that solids begin to participate in a particular chemical or physical process with their surfaces. The subject of our research is related with surface properties in three aspects: (i) chemical state by studying changes in the surface electron – energy structure occurred as a result of a particular process; (ii) vibrational (phonon, plasmon) structures; (iii) geometric structure – local atomic environment in the amorphous materials or long range order in the monocrystalline surface layers. The studies are performed by irradiating the surfaces with soft X-ray photons (energies of 1253.6 or 1486.6 eV) and electron beams with kinetic energy in the range of 4-250 eV. As a result of these irradiations, electrons from the deep lying and valence energy levels are emitted, as well as processes of inelastic scattering of electrons from the surfaces occur, causing excitations of phonon and plasmon collective oscillations in the surface layers. Therefore, by analyzing the kinetic energies of photoemitted or inelastic scattered electrons, we achieve the three goals of our research activities listed above. An often raised question is the depth of our analysis or the thickness of the surface layers we are examining. It reaches up to 6-8 nm as our experimental technique is most sensitive to the uppermost atomic monolayer of the solids, and this makes our studies particularly suitable for the areas of adsorption, catalysis, corrosion, sensor technology, nanotechnology, thin film formation with different applications and other spheres where the participation of the outermost surface atoms is crucial.
1) K. L. Kostov, F. O. Schumann, S. Polzin, D. Sander, and W. Widdra,
NiO growth on Ag(001): A layer-by-layer vibrational study,
Physical Review B 94 (2016) Art. Num. 075438,
2) Shipochka M., Eliyas A., Stambolova I., Blaskov V., Vassilev S., Simeonova S., Balashev K.,
Synthesis of TiO2 on SnO2 bicomponent system and investigation of its structure and photocatalytic activity,
Materials Chemistry and Physics 220, 2018, pp. 249-259
3) Milenov, T., Dikovska, A., Avdeev, G., Avramova, I., Kirilov, K., Karashanova, D., Terziyska, P., Georgieva, B., Arnaudov, B., Kolev, S., Valcheva, E.,
Pulsed laser deposition of thin carbon films on SiO2/ Si substrates,
Applied Surface Science, (2019) 480, pp. 323-329.
4) M. Milanova, K.L. Kostov, R. Iordanova , L. Aleksandrov , A. Yordanova , T. Mineva,
Local structure, connectivity and physical properties of glasses in the B2O3– Bi2O3-La2O3-WO3 system,
Journal of Non-Crystalline Solids 516 (2019) pp.35-44,
5) S. Kozhukharov, Ch. Girginov, A. Tsanev and M. Petrova,
Elucidation of the Anodization and Silver Incorporation Impact on the Surface Properties of AA1050 Aluminum Alloy,
J. Electrochem. Soc., 166 (10) (2019) C231-C242
6) T. Dilova, G. Atanasova, A.Og. Dikovska, N.N. Nedyalkov,
The effect of light irradiation on the gas-sensing properties of nanocomposites based on ZnO and Ag nanoparticles,
Applied Surface Science 505 (2020) 144625,
· Serbian Academy of Sciences and Arts
Prof. Dr. Wolf Widdra, Institute of Physics, Marthin-Luther University, Halle/Wittenberg, Germany, in the framework of the project SFB-762: „Functional oxidic interfaces: Stress and lattice dynamics in multiferroic systems”.
Prof. Dr. Bruno Alonso, Prof. Dr. Emmanuel Belamie and Prof. Dr. Tzonka Mineva, Institut Charles Gerhardt Montpellier, Equipe “Matériaux Avancés pour la Catalyse et la Santé", Montpellier, France, subject: Spectroscopic study of biopolymer-oxide nano-composites using XPS and NMR.