@article{MTMT:35179465, title = {Optical Activity and Phase Transformations in γ/β Ga2O3 Bilayers Under Annealing}, url = {https://m2.mtmt.hu/api/publication/35179465}, author = {Azarov, Alexander and Galeckas, Augustinas and Cora, Ildikó and Fogarassy, Zsolt and Venkatachalapathy, Vishnukanthan and Monakhov, Eduard and Kuznetsov, Andrej}, doi = {10.1002/adom.202401325}, journal-iso = {ADV OPT MATER}, journal = {ADVANCED OPTICAL MATERIALS}, volume = {in press}, unique-id = {35179465}, issn = {2195-1071}, abstract = {Gallium oxide (Ga2O3) can be crystallized in several polymorphs exhibiting different physical properties. In this work, polymorphic structures consisting of the cubic defective spinel (gamma) film on the top of the monoclinic (beta) substrate are fabricated by disorder-induced ordering, known to be a practical way to stack these polymorphs together. Such bilayer structures are annealed to investigate optical properties and phase transformations. Specifically, photoluminescence and diffuse reflectance spectroscopy are combined with transmission electron microscopy, Rutherford backscattering/channeling spectrometry and X-ray diffraction to monitor the evolutions. As a result, a two-stage annealing kinetics is observed in gamma/beta Ga2O3 bilayers associated with the epitaxial gamma-to-beta regrowth at the interface at temperatures below 700 degrees C and a non-planar gamma-to-beta phase transformation starting at higher temperatures. Thus, the present data enhance understanding of the polymorphism in Ga2O3, interconnecting the phase transformation kinetics with the evolution of the optical properties.}, keywords = {PHOTOLUMINESCENCE; phase transformations; Diffuse Reflectance; gallium oxide; Materials Science, Multidisciplinary}, year = {2024}, eissn = {2195-1071}, orcid-numbers = {Azarov, Alexander/0000-0003-0602-9624; Fogarassy, Zsolt/0000-0003-4981-1237} } @article{MTMT:34714394, title = {Atomic layer deposited Fe-sulphide layers with pyrrhotite structure controlled by the deposition temperature}, url = {https://m2.mtmt.hu/api/publication/34714394}, author = {Baji, Zsófia and Pécz, Béla and Fogarassy, Zsolt and Szabó, Zoltán and Cora, Ildikó}, doi = {10.1016/j.tsf.2024.140267}, journal-iso = {THIN SOLID FILMS}, journal = {THIN SOLID FILMS}, volume = {794}, unique-id = {34714394}, issn = {0040-6090}, abstract = {Atomic layer deposition was used to grow epitaxial iron sulphide layers on α-Al2O3 substrates. According to the transmission electron microscopic measurements, these Fe-sulphide films had 1C pyrrhotite structure (Fe1-xS). In the case of pyrrhotite materials, both the magnetic and electric properties depend significantly on their iron content and on the ordering of iron vacancies. By tuning the parameters of the atomic layer deposition method, the structure of epitaxial pyrrhotite films could be controlled, thus the electronic properties of the Fe1-xS films could be influenced: At deposition temperatures below 350°C, the structure contained many faults, and the layers were n type semiconductors, while at higher temperatures, the resulting films were p-type with excellent crystalline structures with disordered vacancies. A post deposition annealing could further improve the crystallinity and induce p-type conductivity.}, keywords = {Atomic layer deposition; Thermal annealing; Pyrrhotite; Iron sulphide}, year = {2024}, eissn = {1879-2731}, orcid-numbers = {Baji, Zsófia/0000-0001-5051-3128; Pécz, Béla/0000-0002-4651-6972; Fogarassy, Zsolt/0000-0003-4981-1237; Szabó, Zoltán/0000-0002-2150-1459} } @article{MTMT:34714097, title = {Structural and electrical investigation of Al/Ti/TiN/Au based N-face n-GaN contact stack}, url = {https://m2.mtmt.hu/api/publication/34714097}, author = {Fogarassy, Zsolt and Wójcicka, Aleksandra and Cora, Ildikó and Rácz, Adél Sarolta and Grzanka, Szymon and Dodony, Erzsébet and Perlin, Piotr and Borysiewicz, Michał A.}, doi = {10.1016/j.mssp.2024.108250}, journal-iso = {MAT SCI SEMICON PROC}, journal = {MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING}, volume = {175}, unique-id = {34714097}, issn = {1369-8001}, abstract = {In this work, the structure of Ti/Al/TiN/Au contact layer stack on the N-face of a single-crystal n-GaN substrate is studied after heat treatment at 750 °C. Since TiN is widely regarded as a diffusion barrier in the stack, the formed structures with three different initial TiN thicknesses (15, 60 and 90 nm) in the contact layers are investigated in detail. The primary tool used for the structural investigations was a (scanning) transmission electron microscope ((S)TEM). In all three samples a low resistivity ohmic contact was formed. However, the TiN layer has not completely blocked the diffusion for any of the samples and both Al and Au diffused through the TiN layer at the temperature of 750 °C. As a result of the heat treatment, a complex AlN/TiN/Au2Al/TiN/Au + Al2.67O4 stack was formed on the surface of the GaN substrate. The measurements have not shown the often reported Ti–Al alloy phase in the samples. The formation of the AlN and TiN layers can be explained by the separation of N from GaN creating N vacancies in the GaN substrate which could help the formation of the ohmic behavior.}, year = {2024}, eissn = {1873-4081}, orcid-numbers = {Fogarassy, Zsolt/0000-0003-4981-1237} } @article{MTMT:34653875, title = {Towards aluminum oxide/aluminum nitride insulating stacks on 4H–SiC by atomic layer deposition}, url = {https://m2.mtmt.hu/api/publication/34653875}, author = {Galizia, Bruno and Fiorenza, Patrick and Schilirò, Emanuela and Pécz, Béla and Fogarassy, Zsolt and Greco, Giuseppe and Saggio, Mario and Cascino, Salvatore and Lo, Nigro Raffaella and Roccaforte, Fabrizio}, doi = {10.1016/j.mssp.2024.108244}, journal-iso = {MAT SCI SEMICON PROC}, journal = {MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING}, volume = {174}, unique-id = {34653875}, issn = {1369-8001}, abstract = {Stacked aluminum oxide/aluminum nitride (Al2O3/AlN) layers were deposited on n-type (0001) 4H–SiC by atomic layer deposition (ALD) processes. The structural and chemical properties have been investigated and are consistent with the growth of ∼9 nm oriented (0001) AlN layer, and an upper 20 nm amorphous Al2O3 layer. The entire Al2O3/AlN stack was electrically characterized and compared with respect to a single Al2O3 layer having the same total thickness. The Al2O3/AlN bilayer exhibited a higher dielectric constant (κ = 8.7), a significant reduction of the oxide trapped charges (NOT) from 7.8 × 1012 to 1.8 × 1012 cm−2, as well as a decrease of a factor 2 of the interface traps density (Dit) compared with the Al2O3 single layer values. A large positive flat band voltage shift was observed in the C–V curves acquired on MIS capacitors. The comparison of the behaviour of MIS capacitors fabricated on both n-type and p-type 4H–SiC demonstrated that deep interface states (near the 4H–SiC mid gap) acting as acceptors or donors for the n-type and p-type MIS contribute to the observed behavior. This hypothesis has been also corroborated by TCAD simulations.}, year = {2024}, eissn = {1873-4081}, orcid-numbers = {Pécz, Béla/0000-0002-4651-6972; Fogarassy, Zsolt/0000-0003-4981-1237} } @article{MTMT:34193521, title = {Structural and electrical correlation in aluminum nitride thin films grown by plasma enhanced atomic layer deposition as interface insulating layers on silicon carbide (4H-SiC)}, url = {https://m2.mtmt.hu/api/publication/34193521}, author = {Galizia, Bruno and Fiorenza, Patrick and Bongiorno, Corrado and Pécz, Béla and Fogarassy, Zsolt and Schilirò, Emanuela and Giannazzo, Filippo and Roccaforte, Fabrizio and Nigro, Raffaella Lo}, doi = {10.1016/j.mee.2023.112103}, journal-iso = {MICROELECTRON ENG}, journal = {MICROELECTRONIC ENGINEERING}, volume = {283}, unique-id = {34193521}, issn = {0167-9317}, year = {2024}, eissn = {1873-5568}, orcid-numbers = {Pécz, Béla/0000-0002-4651-6972; Fogarassy, Zsolt/0000-0003-4981-1237} } @article{MTMT:34832862, title = {Optimized Pt–Co Alloy Nanoparticles for Reverse Water–Gas Shift Activation of CO 2}, url = {https://m2.mtmt.hu/api/publication/34832862}, author = {Szamosvölgyi, Ákos and Pitó, Ádám and Efremova, Anastasiia and Baán, Kornélia and Kutus, Bence and Suresh, Mutyala and Sápi, András and Szenti, Imre and Kiss, János and Kolonits, Tamás and Fogarassy, Zsolt and Pécz, Béla and Kukovecz, Ákos and Kónya, Zoltán}, doi = {10.1021/acsanm.4c00111}, journal-iso = {ACS APPL NANO MATER}, journal = {ACS APPLIED NANO MATERIALS}, volume = {7}, unique-id = {34832862}, year = {2024}, eissn = {2574-0970}, pages = {9968-9977}, orcid-numbers = {Baán, Kornélia/0000-0001-7511-4422; Kutus, Bence/0000-0001-5023-0152; Sápi, András/0000-0001-6557-0731; Kolonits, Tamás/0000-0002-5836-4398; Fogarassy, Zsolt/0000-0003-4981-1237; Pécz, Béla/0000-0002-4651-6972; Kukovecz, Ákos/0000-0003-0716-9557; Kónya, Zoltán/0000-0002-9406-8596} } @article{MTMT:34555692, title = {Irreversible evolution of dislocation pile-ups during cyclic microcantilever bending}, url = {https://m2.mtmt.hu/api/publication/34555692}, author = {Ugi, Dávid and Zoller, K. and Lukács, K. and Fogarassy, Zsolt and Groma, István and Kalácska, Szilvia and Schulz, K. and Ispánovity, Péter Dusán}, doi = {10.1016/j.matdes.2024.112682}, journal-iso = {MATER DESIGN}, journal = {MATERIALS AND DESIGN}, volume = {238}, unique-id = {34555692}, issn = {0264-1275}, year = {2024}, eissn = {1873-4197}, orcid-numbers = {Ugi, Dávid/0000-0002-8400-2307; Fogarassy, Zsolt/0000-0003-4981-1237; Groma, István/0000-0002-6644-1365; Kalácska, Szilvia/0000-0001-5601-5859; Ispánovity, Péter Dusán/0000-0002-9956-0061} } @article{MTMT:33138741, title = {Encapsulation of the Graphene Nanoribbon Precursor 1, 2, 4‐trichlorobenzene in Boron Nitride Nanotubes at Room Temperature}, url = {https://m2.mtmt.hu/api/publication/33138741}, author = {Cadena Nogales, Ana Cristina and Pekker, Áron and Botka, Bea and Dodony, Erzsébet and Fogarassy, Zsolt and Pécz, Béla and Kamarás, Katalin}, doi = {10.1002/pssr.202200284}, journal-iso = {PHYS STATUS SOLIDI-R}, journal = {PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS}, volume = {17}, unique-id = {33138741}, issn = {1862-6254}, year = {2023}, eissn = {1862-6270}, orcid-numbers = {Botka, Bea/0000-0003-3707-3097; Fogarassy, Zsolt/0000-0003-4981-1237; Pécz, Béla/0000-0002-4651-6972; Kamarás, Katalin/0000-0002-0390-3331} } @CONFERENCE{MTMT:34487420, title = {DIFFRAKCIÓS INTENZITÁS MÉRÉSEK TEM-BEN II.: AZ EWALD KORREKCIÓ KITERJESZTÉSE. Diffracted intensity measurements in TEM II.: Extension of the Ewald correction}, url = {https://m2.mtmt.hu/api/publication/34487420}, author = {Dodony, Erzsébet and Dódony, István and Fogarassy, Zsolt and Pekker, Péter and Sáfrán, György}, booktitle = {A Magyar Mikroszkópos Társaság éves konferenciájának kivonatkönyve 2023 : Book of the Abstracts of the Annual Conference of HSM 2023}, unique-id = {34487420}, year = {2023}, pages = {28-31}, orcid-numbers = {Fogarassy, Zsolt/0000-0003-4981-1237; Pekker, Péter/0000-0002-0463-0742; Sáfrán, György/0000-0003-3708-3551} } @CONFERENCE{MTMT:34487369, title = {A γ -NIKKEL-SZILICID SZERKEZETI VÁLTOZATOSSÁGA. Structural variability of the γ-nickel-silicide}, url = {https://m2.mtmt.hu/api/publication/34487369}, author = {Dodony, Erzsébet and Dódony, István and Fogarassy, Zsolt and Pekker, Péter and Sáfrán, György}, booktitle = {A Magyar Mikroszkópos Társaság éves konferenciájának kivonatkönyve 2023 : Book of the Abstracts of the Annual Conference of HSM 2023}, unique-id = {34487369}, year = {2023}, pages = {26-28}, orcid-numbers = {Fogarassy, Zsolt/0000-0003-4981-1237; Pekker, Péter/0000-0002-0463-0742; Sáfrán, György/0000-0003-3708-3551} }