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Senad Isaković

Faculty of Science, University of Sarajevo

Društvene mreže:

Igor Mekterović, Gabrijela Svalina, Senad Isaković, M. Mičetić

Grazing-incidence small-angle X-ray scattering (GISAXS) is a powerful method for the structural analysis of ordered arrays of nanoparticles, quantum dots, or similar objects. However, for the correct interpretation of the measured GISAXS intensity distributions, a proper data analysis, including a suitable model, is required. Here, we demonstrate a software platform, GisaxStudio, aimed at the analysis and simulation of 2D GISAXS intensity distributions from ordered lattices of different nanoparticles. It contains several models that satisfactorily describe the GISAXS from 3D lattices or crystals of nanoparticles prepared by the self-assembly processes, pre-pattering, or ion-beam interaction with the material within their tracks. It also supports different shapes of nanoparticles, including core-shell structure with the center of core possibly displaced from the center of the shell. The software is very useful for fast and accurate GISAXS data analysis.

Senad Isaković, M. Đekić, Marija Tkalčević, Denis Boršćak, Ivana Periša, S. Bernstorff, M. Mičetić

The properties of semiconductor materials can be strongly affected by the addition of metallic nanoparticles. Here we investigate the properties of SiC+Au and Si3N4+Au thin films prepared by magnetron sputtering deposition followed by thermal annealing. The influence of gold addition on the optical and electrical properties is explored. We show the formation of self-assembled Au nanoparticles in SiC and Si3N4, with the size and arrangement properties determined by the deposition and annealing conditions. Both SiC- and Si3N4-based films show an increase in the overall absorption with increasing Au content, and its decrease with increasing annealing temperature. All films show the presence of surface plasmon resonance, whose peaks shift toward larger wavelengths with increasing Au nanoparticle size. The resistivity significantly drops with the Au content increase for both types of matrices, although the resistivity of Si3N4-based films is much higher. The incorporated quantity of Au in the host matrix was chosen in such a way to demonstrate that a huge range of optical and electrical characteristics is achievable. The materials are very interesting for application in opto-electronic devices.

Ivana Periša, Marija Tkalčević, Senad Isaković, Lovro Basioli, M. Ivanda, S. Bernstorff, M. Mičetić

We investigated the production conditions and optoelectrical properties of thin film material consisting of regularly ordered core/shell Ge/Al and Ge/Si3N4/Al quantum dots (QDs) in an alumina matrix. The materials were produced by self–assembled growth achieved by means of multilayer magnetron sputtering deposition. We demonstrated the successful fabrication of well-ordered 3D lattices of Ge/Al and Ge/Si3N4/Al core/shell quantum dots with a body-centred tetragonal arrangement within the Al2O3 matrix. The addition of shells to the Ge core enables a strong tuning of the optical and electrical properties of the material. An Al shell induces a bandgap shift toward smaller energies, and, in addition, it prevents Ge oxidation. The addition of a thin Si3N4 shell induces huge changes in the material spectral response, i.e., in the number of extracted excitons produced by a single photon. It increases both the absolute value and the width of the spectral response. For the best sample, we achieved an enhancement of over 250% of the produced number of excitons in the measured energy range. The observed changes are, as it seems, the consequence of the large tensile strain in Ge QDs which is induced by the Si3N4 shell addition and which is measured to be about 3% for the most strained QDs. The tensile strain causes activation of the direct bandgap of germanium, which has a very strong effect on the spectral response of the material.

Apart from the main apparatus of ATLAS, a new ATLAS Forward Proton (AFP) detector is installed in order to measure the momentum and emission angle of scattered protons subjected to the elastic collisions. Data collected by the AFP is used, among other, for Data Quality Monitoring (DQM). DQM is implemented via DQM code. Actions that needs to be taken before code compilation, together with prescription on running the code, have been analyzed. Various components of the DQM code were inspected, and related to its output results. In addition, code migration to the new software framework AthenaMT was investigated.

J. Gainer, M. González-Alonso, A. Greljo, Senad Isaković, G. Isidori, A. Korytov, J. Lykken, D. Marzocca, Konstantin T. Matchev et al.

J. Gainer, M. González-Alonso, A. Greljo, Senad Isaković, G. Isidori, A. Korytov, J. Lykken, D. Marzocca, Konstantin T. Matchev et al.

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