TY - JOUR AU - Baji, Zsófia AU - Pécz, Béla AU - Fogarassy, Zsolt AU - Szabó, Zoltán AU - Cora, Ildikó TI - Atomic layer deposited Fe-sulphide layers with pyrrhotite structure controlled by the deposition temperature JF - THIN SOLID FILMS J2 - THIN SOLID FILMS VL - in press PY - 2024 SN - 0040-6090 DO - 10.1016/j.tsf.2024.140267 UR - https://m2.mtmt.hu/api/publication/34714394 ID - 34714394 AB - 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. LA - English DB - MTMT ER - TY - JOUR AU - Fogarassy, Zsolt AU - Wójcicka, Aleksandra AU - Cora, Ildikó AU - Rácz, Adél Sarolta AU - Grzanka, Szymon AU - Dodony, Erzsébet AU - Perlin, Piotr AU - Borysiewicz, Michał A. TI - Structural and electrical investigation of Al/Ti/TiN/Au based N-face n-GaN contact stack JF - MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING J2 - MAT SCI SEMICON PROC VL - 175 PY - 2024 PG - 12 SN - 1369-8001 DO - 10.1016/j.mssp.2024.108250 UR - https://m2.mtmt.hu/api/publication/34714097 ID - 34714097 AB - 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. LA - English DB - MTMT ER - TY - JOUR AU - Galizia, Bruno AU - Fiorenza, Patrick AU - Schilirò, Emanuela AU - Pécz, Béla AU - Fogarassy, Zsolt AU - Greco, Giuseppe AU - Saggio, Mario AU - Cascino, Salvatore AU - Lo, Nigro Raffaella AU - Roccaforte, Fabrizio TI - Towards aluminum oxide/aluminum nitride insulating stacks on 4H–SiC by atomic layer deposition JF - MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING J2 - MAT SCI SEMICON PROC VL - 174 PY - 2024 PG - 7 SN - 1369-8001 DO - 10.1016/j.mssp.2024.108244 UR - https://m2.mtmt.hu/api/publication/34653875 ID - 34653875 AB - 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. LA - English DB - MTMT ER - TY - JOUR AU - Galizia, Bruno AU - Fiorenza, Patrick AU - Bongiorno, Corrado AU - Pécz, Béla AU - Fogarassy, Zsolt AU - Schilirò, Emanuela AU - Giannazzo, Filippo AU - Roccaforte, Fabrizio AU - Nigro, Raffaella Lo TI - 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) JF - MICROELECTRONIC ENGINEERING J2 - MICROELECTRON ENG VL - 283 PY - 2024 PG - 7 SN - 0167-9317 DO - 10.1016/j.mee.2023.112103 UR - https://m2.mtmt.hu/api/publication/34193521 ID - 34193521 LA - English DB - MTMT ER - TY - JOUR AU - Rácz, Adél Sarolta AU - Kun, Péter AU - Kerner, Zsolt Gábor AU - Fogarassy, Zsolt AU - Menyhárd, Miklós TI - Tungsten Carbide Nanolayer Formation by Ion Beam Mixing with Argon and Xenon Ions for Applications as Protective Coatings JF - ACS APPLIED NANO MATERIALS J2 - ACS APPL NANO MATER VL - 6 PY - 2023 IS - 5 SP - 3816 EP - 3824 PG - 9 SN - 2574-0970 DO - 10.1021/acsanm.2c05505 UR - https://m2.mtmt.hu/api/publication/34538351 ID - 34538351 LA - English DB - MTMT ER - TY - CONF AU - Dodony, Erzsébet AU - Dódony, István AU - Fogarassy, Zsolt AU - Pekker, Péter AU - Sáfrán, György ED - Steinbach, Gábor TI - DIFFRAKCIÓS INTENZITÁS MÉRÉSEK TEM-BEN II.: AZ EWALD KORREKCIÓ KITERJESZTÉSE. Diffracted intensity measurements in TEM II.: Extension of the Ewald correction TS - Diffracted intensity measurements in TEM II.: Extension of the Ewald correction T2 - A Magyar Mikroszkópos Társaság éves konferenciájának kivonatkönyve 2023 : Book of the Abstracts of the Annual Conference of HSM 2023 PY - 2023 SP - 28 EP - 31 PG - 4 UR - https://m2.mtmt.hu/api/publication/34487420 ID - 34487420 N1 - Előadás LA - English DB - MTMT ER - TY - CONF AU - Dodony, Erzsébet AU - Dódony, István AU - Fogarassy, Zsolt AU - Pekker, Péter AU - Sáfrán, György ED - Steinbach, Gábor TI - A γ -NIKKEL-SZILICID SZERKEZETI VÁLTOZATOSSÁGA. Structural variability of the γ-nickel-silicide TS - Structural variability of the γ-nickel-silicide T2 - A Magyar Mikroszkópos Társaság éves konferenciájának kivonatkönyve 2023 : Book of the Abstracts of the Annual Conference of HSM 2023 PY - 2023 SP - 26 EP - 28 PG - 3 UR - https://m2.mtmt.hu/api/publication/34487369 ID - 34487369 N1 - Előadás LA - English DB - MTMT ER - TY - JOUR AU - Varga, Gábor AU - Szenti, Imre AU - Kiss, János AU - Baán, Kornélia AU - Halasi, Gyula AU - Óvári, László AU - Szamosvölgyi, Ákos AU - Mucsi, Róbert AU - Dodony, Erzsébet AU - Fogarassy, Zsolt AU - Pécz, Béla AU - Olivi, Luca AU - Sápi, András AU - Kukovecz, Ákos AU - Kónya, Zoltán TI - Decisive role of Cu/Co interfaces in copper cobaltite derivatives for high performance CO2 methanation catalyst JF - JOURNAL OF CO2 UTILIZATION J2 - J CO2 UTIL VL - 75 PY - 2023 PG - 13 SN - 2212-9820 DO - 10.1016/j.jcou.2023.102582 UR - https://m2.mtmt.hu/api/publication/34120023 ID - 34120023 AB - Thermo-catalytic bio-SNG (CH4) production is one of the useful tools for converting waste to gaseous fuels through CO2 conversion. To abundant properly, however, efficient, robust and cost-effective catalysts would be required. Bimetallic systems based on transition metals seem to be promising candidates for this task. The CoCu bimetallic system with in-situ generated interfaces was synthesized and used as a catalyst for CO2 methanation. The in-depth analysis of the structure-activity-selectivity relationships involving XRD, (NAP-)XPS, EXAFS and TEM-EDX revealed that the co-existence of Co0, CoO, and Cu0 in the proper distribution on the surface can ensure the selective production of methane. To fine-tune the surface composition of the bimetallic systems, a systematic alteration of the Cu:Co ratio in the precursor spinel structures must be performed. Cu0.4Co2.6O4 derivative, stabilizing subsurface Cu(I)–O specimen, showed the best performance with high activity (12,800 nmol g–1 s–1) and a remarkable selectivity of 65–85% for methane in a wide temperature range (250–425 °C). In studying the mechanistic aspects of methanation, it has been shown that the hydrogenation of active carbon at the surface or below the surface is the key step for the production of methane. So far, this cobalt-catalyzed sub-step has been proposed in catalytic Fischer-Tropsch syntheses. LA - English DB - MTMT ER - TY - JOUR AU - Maj, Ł. AU - Fogarassy, Zsolt AU - Wojtas, D. AU - Jarzębska, A. AU - Muhaffel, F. AU - Sulyok, Attila AU - Góral, A. AU - Kulczyk, M. AU - Çimenoğlu, H. AU - Bieda, M. TI - In-situ formation of Ag nanoparticles in the MAO coating during the processing of cp-Ti JF - SCIENTIFIC REPORTS J2 - SCI REP VL - 13 PY - 2023 IS - 1 PG - 7 SN - 2045-2322 DO - 10.1038/s41598-023-29999-7 UR - https://m2.mtmt.hu/api/publication/33733765 ID - 33733765 LA - English DB - MTMT ER - TY - JOUR AU - Ugi, Dávid AU - Péterffy, Gábor AU - Lipcsei, S. AU - Fogarassy, Zsolt AU - Szilágyi, Edit AU - Groma, István AU - Ispánovity, Péter Dusán TI - Irradiation-induced strain localization and strain burst suppression investigated by microcompression and concurrent acoustic emission experiments JF - MATERIALS CHARACTERIZATION J2 - MATER CHARACT VL - 199 PY - 2023 PG - 11 SN - 1044-5803 DO - 10.1016/j.matchar.2023.112780 UR - https://m2.mtmt.hu/api/publication/33728503 ID - 33728503 LA - English DB - MTMT ER -