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 - Mazzolini, Piero AU - Fogarassy, Zsolt AU - Parisini, Antonella AU - Mezzadri, Francesco AU - Diercks, David AU - Bosi, Matteo AU - Seravalli, Luca AU - Sacchi, Anna AU - Spaggiari, Giulia AU - Bersani, Danilo AU - Bierwagen, Oliver AU - Janzen, Benjamin Moritz AU - Marggraf, Marcella Naomi AU - Wagner, Markus R. AU - Cora, Ildikó AU - Pécz, Béla AU - Tahraoui, Abbes AU - Bosio, Alessio AU - Borelli, Carmine AU - Leone, Stefano AU - Fornari, Roberto TI - Silane‐Mediated Expansion of Domains in Si‐Doped κ‐Ga 2 O 3 Epitaxy and its Impact on the In‐Plane Electronic Conduction JF - ADVANCED FUNCTIONAL MATERIALS J2 - ADV FUNCT MATER VL - 33 PY - 2023 IS - 2 PG - 14 SN - 1616-301X DO - 10.1002/adfm.202207821 UR - https://m2.mtmt.hu/api/publication/33213269 ID - 33213269 LA - English DB - MTMT ER - TY - CONF AU - Olasz, Dániel AU - Kovácsné Kis, Viktória AU - Cora, Ildikó AU - Sáfrán, György ED - Steinbach, Gábor TI - Y-TI-O VÉKONYRÉTEGRENDSZER ÖSSZETÉTELFÜGGŐ SZERKEZETE: A PIROKLÓR SZERKEZETŰ Y2TI2O7 HATÉKONY ELŐÁLLÍTÁSA. Composition dependent structure of the Y-Ti-O thin film system: efficient synthesis of Y2Ti2O7 with pyrochlore structure TS - Composition dependent structure of the Y-Ti-O thin film system: efficient synthesis of Y2Ti2O7 with pyrochlore structure T2 - A Magyar Mikroszkópos Társaság éves konferenciájának kivonatkönyve 2023 : Book of the Abstracts of the Annual Conference of HSM 2023 PY - 2023 SP - 68 EP - 70 PG - 3 UR - https://m2.mtmt.hu/api/publication/34487511 ID - 34487511 N1 - Előadás LA - English DB - MTMT ER - TY - JOUR AU - Bódis, Eszter AU - Cora, Ildikó AU - Fogarassy, Zsolt AU - Veres, Miklós AU - Németh, Péter TI - High-temperature evolution of diamond-SiC composites JF - PROCESSING AND APPLICATION OF CERAMICS J2 - PROC APPL CERAMICS VL - 16 PY - 2022 IS - 1 SP - 69 EP - 77 PG - 9 SN - 1820-6131 DO - 10.2298/PAC2201069B UR - https://m2.mtmt.hu/api/publication/32909697 ID - 32909697 LA - English DB - MTMT ER - TY - JOUR AU - Baji, Zsófia AU - Cora, Ildikó AU - Horváth, Zsolt Endre AU - Agócs, Emil AU - Szabó, Zoltán TI - Atomic layer deposition and characterization of Zn-doped Ga2O3 films JF - JOURNAL OF VACUUM SCIENCE AND TECHNOLOGY A-VACUUM SURFACES AND FILMS J2 - J VAC SCI TECHNOL A VL - 39 PY - 2021 IS - 3 PG - 9 SN - 0734-2101 DO - 10.1116/6.0000838 UR - https://m2.mtmt.hu/api/publication/32055088 ID - 32055088 AB - The present work focuses on the atomic layer deposition (ALD), annealing, and Zn doping of gallium oxide (Ga2O3) films using a novel Ga precursor, hexakis-dimethylamino-digallium. As ALD deposited Ga2O3 films are always amorphous, the optimal annealing procedure had to be found to achieve crystalline beta -Ga2O3. The bandgaps and dielectric properties of the layers were measured and the effects of the deposition parameters and postdeposition annealing on the electrical properties were determined. The effects of Zn doping on the electrical properties were analyzed, and some crucial issues for application as a UV sensor were addressed. LA - English DB - MTMT ER - TY - JOUR AU - Bosio, A. AU - Parisini, A. AU - Lamperti, A. AU - Borelli, C. AU - Fornasini, L. AU - Bosi, M. AU - Cora, Ildikó AU - Fogarassy, Zsolt AU - Pécz, Béla AU - Zolnai, Zsolt AU - Németh, Attila AU - Vantaggio, S. AU - Fornari, R. TI - n-Type doping of ε-Ga2O3 epilayers by high-temperature tin diffusion JF - ACTA MATERIALIA J2 - ACTA MATER VL - 210 PY - 2021 PG - 9 SN - 1359-6454 DO - 10.1016/j.actamat.2021.116848 UR - https://m2.mtmt.hu/api/publication/31961887 ID - 31961887 LA - English DB - MTMT ER - TY - JOUR AU - Kakanakova-Georgieva, Anelia AU - Giannazzo, Filippo AU - Nicotra, Giuseppe AU - Cora, Ildikó AU - Gueorguiev, Gueorgui K. AU - Persson, Per O.Å. AU - Pécz, Béla TI - Material proposal for 2D indium oxide JF - APPLIED SURFACE SCIENCE J2 - APPL SURF SCI VL - 548 PY - 2021 PG - 6 SN - 0169-4332 DO - 10.1016/j.apsusc.2021.149275 UR - https://m2.mtmt.hu/api/publication/31872395 ID - 31872395 AB - Realization of semiconductor materials at the two-dimensional (2D) limit can elicit exceptional and diversified performance exercising transformative influence on modern technology. We report experimental evidence for the formation of conceptually new 2D indium oxide (InO) and its material characteristics. The formation of 2D InO was harvested through targeted intercalation of indium (In) atoms and deposition kinetics at graphene/SiC interface using a robust metal organic chemical vapor deposition (MOCVD) process. A distinct structural configuration of two sub-layers of In atoms in “atop” positions was imaged by scanning transmission electron microscopy (STEM). The bonding of oxygen atoms to indium atoms was indicated using electron energy loss spectroscopy (EELS). A wide bandgap energy measuring a value of 4.1 eV was estimated by conductive atomic force microscopy measurements (C-AFM) for the 2D InO. LA - English DB - MTMT ER - TY - JOUR AU - Kakanakova-Georgieva, Anelia AU - Ivanov, Ivan G. AU - Suwannaharn, Nattamon AU - Hsu, Chih-Wei AU - Cora, Ildikó AU - Pécz, Béla AU - Giannazzo, Filippo AU - Sangiovanni, Davide G. AU - Gueorguiev, Gueorgui K. TI - MOCVD of AlN on epitaxial graphene at extreme temperatures JF - CRYSTENGCOMM J2 - CRYSTENGCOMM VL - 23 PY - 2021 IS - 2 SP - 385 EP - 390 PG - 6 SN - 1466-8033 DO - 10.1039/D0CE01426E UR - https://m2.mtmt.hu/api/publication/31675223 ID - 31675223 AB - The initial stages of metal organic chemical vapor deposition (MOCVD) of AlN on epitaxial graphene at temperatures in excess of 1200 °C have been rationalized. The use of epitaxial graphene, in conjunction with high deposition temperatures, can deliver on the realization of nanometer thin AlN whose material quality is characterized by the appearance of luminescent centers with narrow spectral emission at room temperature. It has been elaborated, based on our previous comprehensive ab initio molecular dynamics simulations, that the impact of graphene on AlN growth consists in the way it promotes dissociation of the trimethylaluminum, (CH3)3Al, precursor with subsequent formation of Al adatoms during the initial stages of the deposition process. The high deposition temperatures ensure adequate surface diffusion of the Al adatoms which is an essential factor in material quality enhancement. The role of graphene in intervening with the dissociation of another precursor, trimethylgallium, (CH3)3Ga, has accordingly been speculated by presenting a case of propagation of ultrathin GaN of semiconductor quality. A lower deposition temperature of 1100 °C in this case has better preserved the structural integrity of epitaxial graphene. Breakage and decomposition of the graphene layers has been deduced in the case of AlN deposition at temperatures in excess of 1200 °C. LA - English DB - MTMT ER - TY - JOUR AU - Schilirò, Emanuela AU - Giannazzo, Filippo AU - Di Franco, Salvatore AU - Greco, Giuseppe AU - Fiorenza, Patrick AU - Roccaforte, Fabrizio AU - Prystawko, Paweł AU - Kruszewski, Piotr AU - Leszczynski, Mike AU - Cora, Ildikó AU - Pécz, Béla AU - Fogarassy, Zsolt AU - Lo Nigro, Raffaella TI - Highly Homogeneous Current Transport in Ultra-Thin Aluminum Nitride (AlN) Epitaxial Films on Gallium Nitride (GaN) Deposited by Plasma Enhanced Atomic Layer Deposition JF - NANOMATERIALS J2 - NANOMATERIALS-BASEL VL - 11 PY - 2021 IS - 12 PG - 10 SN - 2079-4991 DO - 10.3390/nano11123316 UR - https://m2.mtmt.hu/api/publication/32526762 ID - 32526762 LA - English DB - MTMT ER -