I am Professor of Physics at the University of Debrecen, Faculty of Science and Technology, Institute of Physics, Department of Solid State Physics. My research is centred on nanoscale materials science, with special emphasis on interfaces, diffusion, solid-state reactions, thin films, multilayers, nanoparticles, atomic layer deposition and functional nanostructures.
I graduated in Physics from Lajos Kossuth University, Debrecen, Hungary, in 1998. I obtained my PhD in Materials Science from the University of Aix-Marseille III, France, and my PhD in Physics, specialized in Solid State Physics, from the University of Debrecen. In 2010, I received my Habilitation in Physics from the University of Debrecen. In 2017, I was awarded the title Doctor of the Hungarian Academy of Sciences (DSc). (Curriculum Vitae)
My work combines theoretical modelling, computer simulation and experimental thin-film and nanoscale materials characterization. A major part of my earlier research dealt with diffusion and segregation in nanostructures, interface sharpening, anomalous diffusion and solid-state reactions. These studies addressed fundamental questions of how atoms move, how interfaces evolve and how new phases form when the characteristic length scale is reduced to the nanometre range.
In recent years, my research has expanded towards atomic layer deposition (ALD), porous and hollow nanostructures, plasmonic and bimetallic nanoparticles, functional oxide thin films, spectroscopic ellipsometry, optical modelling, barrier coatings on polymers and electrochemical energy storage. Current and emerging topics include ALD-grown Al2O3, ZnO and TiO2-based coatings, inverse opal structures, photocatalytic oxide systems, metal-air batteries, hydrogen-related materials and technologies, high-harmonic generation from structured and rough dielectric thin films, multilayered optical structures and the relationship between nanoscale morphology, interfaces and macroscopic material performance.
Selected research topics and representative publications
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 Interface sharpening in miscible alloys
One of my most widely recognized research results is the discovery and explanation of transient interface sharpening in miscible alloys. In contrast to the usual expectation that diffusion broadens concentration profiles, we showed that initially diffuse interfaces may sharpen under suitable conditions. This effect was first predicted by computer simulations and later verified experimentally, including synchrotron radiation studies and atom probe tomography.
This topic connects fundamental diffusion theory with practical materials design, since sharper interfaces are important in multilayers, x-ray and neutron mirrors, magnetic multilayers and microelectronic structures.
Erdélyi Z, Sladecek M, Stadler Lorenz-M, Zizak I, Langer GA, Kis-Varga M, Beke DL, Sepiol B
Transient Interface Sharpening in Miscible Alloys
SCIENCE 306: pp. 1913-1915. (2004) Full text
Erdélyi Z, Szabó IA, Beke DL
Interface sharpening instead of broadening by diffusion in ideal binary alloys
PHYSICAL REVIEW LETTERS 89:(16) Paper 165901. 4 p. (2002) Full text
Balogh Z, Chellali MR, Greiwe GH, Schmitz G, Erdélyi Z
Interface sharpening in miscible Ni/Cu multilayers studied by atom probe tomography
APPLIED PHYSICS LETTERS 99:(18) Paper 181902. (2011) Full text
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 Reactive diffusion, phase formation and stresses in nanostructures
Another central topic of my research is reactive diffusion and phase formation in nanoscale systems. We developed analytical and numerical models for diffusion-controlled solid-state reactions in planar, spherical and other curved geometries. These models include elastic stress, plastic relaxation, vacancy effects and thermodynamic driving forces for compound formation.
Such models are especially relevant for core-shell particles, multilayers and nanometric diffusion couples, where geometry, stress and vacancy transport can significantly influence reaction kinetics and phase stability.
Erdélyi Z, Schmitz G
Reactive diffusion and stresses in spherical geometry
ACTA MATERIALIA 60:(4) pp. 1807-1817. (2012) Full text
Parditka B, Tomán J, Cserháti C, Jánosfalvi Zs, Csik A, Zizak I, Feyerherm R, Schmitz G, Erdélyi Z
The earliest stage of phase growth in sharp concentration gradients
ACTA MATERIALIA 87: pp. 111-120. (2015) Full text
Erdélyi Z, Beke DL, Taranovskyy A
Dissolution and off-stoichiometric formation of compound layers in solid state reactions
APPLIED PHYSICS LETTERS 92:(13) Art. No. 133110. (2008) Full text
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 Solid-state reactions on the nanoscale
I have studied solid-state reactions mainly in technologically important Si-based binary systems, including Ni-Si, Co-Si and Cu-Si. These reactions are important for thin-film contacts, microelectronics and nanoscale phase formation. The work combined theory, computer simulation and a broad range of experimental techniques such as SNMS, XPS, AES, TEM, XRD, synchrotron-based methods and atom probe tomography.
A key question in these studies is how product phases nucleate and grow when the diffusion length is only a few nanometres and when interfaces, defects and non-equilibrium effects dominate the kinetics.
Parditka B, Verezhak M, Balogh Z, Csik A, Langer GA, Beke DL, Ibrahim M, Schmitz G, Erdélyi Z
Phase growth in an amorphous Si–Cu system, as shown by a combination of SNMS, XPS, XRD and APT techniques
ACTA MATERIALIA 61:(19) pp. 7173-7179. (2013) Full text
Lakatos A, Langer GA, Csik A, Cserháti C, Kis-Varga M, Daróczi L, Katona GL, Erdélyi Z, Erdélyi G, Vad K, Beke DL
Nanoscale investigations of shift of individual interfaces in temperature induced processes of Ni-Si system by secondary neutral mass spectrometry
APPLIED PHYSICS LETTERS 97:(23) Paper 233103. 3 p. (2010) Full text
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 Anomalous diffusion and non-Fickian kinetics
Classical Fickian diffusion predicts parabolic interface motion, but nanoscale systems often show deviations from this behaviour. My work contributed to the understanding of anomalous diffusion kinetics, non-parabolic interface shifts and the transition from anomalous to normal diffusion. These studies are relevant whenever diffusion takes place over extremely short distances or in systems where solubility limits, interface effects or finite-size effects become important.
Balogh Z, Erdélyi Z, Beke DL, Langer GA, Csik A, Boyen H-G, Wiedwald U, Ziemann P, Portavoce A, Girardeaux Ch
Transition from anomalous kinetics toward Fickian diffusion for Si dissolution into amorphous Ge
APPLIED PHYSICS LETTERS 92:(14) Art. No. 143104. (2008) Full text
Beke DL, Erdélyi Z
Resolution of the diffusional paradox predicting infinitely fast kinetics on the nanoscale
PHYSICAL REVIEW B 73: 035426. (2006) Full text
Erdélyi Z, Katona G, Beke DL
Nonparabolic nanoscale shift of phase boundaries in binary systems with restricted solubility
PHYSICAL REVIEW B 69: 113407. (2004) Full text
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Porous, plasmonic and bimetallic nanoparticles
Besides planar thin films and multilayers, an important part of my work concerns nanoscale phase separation, morphology control and functional properties in nanoparticles. This includes porous gold nanoparticles, Au/Al2O3 hybrid nanoparticles and bimetallic Ag-Cu nanoparticles. These systems are interesting both from the fundamental point of view of nanoscale thermodynamics and phase separation, and from the application-oriented point of view of plasmonics, optical tunability and nanophotonics.
The Ag-Cu nanoparticle work is a particularly important example where nanoscale size effects modify phase separation behaviour. The porous gold nanoparticle studies show how dealloying, annealing and ALD-based surface passivation can be used to tailor morphology and optical response.
Radnóczi G, Bokányi E, Erdélyi Z, Misják F
Size dependent spinodal decomposition in Cu-Ag nanoparticles
ACTA MATERIALIA 123: pp. 82-89. (2017) Full text
Rao W, Wang D, Kups T, Baradács E, Parditka B, Erdélyi Z, Schaaf P
Nanoporous Gold Nanoparticles and Au/Al2O3 Hybrid Nanoparticles with Large Tunability of Plasmonic Properties
ACS APPLIED MATERIALS & INTERFACES 9:(7) pp. 6273-6281. (2017) Full text
Kosinova A, Wang D, Baradács E, Parditka B, Kups T, Klinger L, Erdélyi Z, Schaaf P, Rabkin E
Tuning the nanoscale morphology and optical properties of porous gold nanoparticles by surface passivation and annealing
ACTA MATERIALIA 127: pp. 108-116. (2017) Full text
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Atomic layer deposition and functional oxide nanostructures
Atomic layer deposition has become a major experimental direction in my recent research. ALD enables the preparation of conformal, thickness-controlled oxide layers on planar, porous and three-dimensional substrates. We use this approach to prepare and study Al2O3, ZnO and TiO2-based coatings, inverse opal structures, hollow nanospheres, multilayers and oxide composites.
These materials are investigated for photocatalysis, optical functionality, gas sensing, barrier protection and interface-controlled performance. This research connects thin-film growth, nanoscale morphology, surface/interface chemistry and application-oriented materials design.
Justh N, Bakos LP, Hernádi K, Kiss G, Réti B, Erdélyi Z, Parditka B, Szilágyi IM
Photocatalytic hollow TiO2 and ZnO nanospheres prepared by atomic layer deposition
SCIENTIFIC REPORTS 7: Paper 4337. (2017) Full text
Lemago HH, Tolezani L, Igricz T, Hessz D, Pál P, Cserháti C, Vecsei G, Sárközi B, Baradács E, Erdélyi Z, Szilágyi IM
Enhanced photocatalysis via inverse opal structures: Synthesis and characterization of TiO2/ZnO and ZnO/TiO2 composites using plasma-enhanced ALD
CERAMICS INTERNATIONAL 51:(1) pp. 339-352. (2025) Full text
Lemago HH, Khauli N, Hessz D, Igricz T, Pál P, Cserháti C, Baradács E, Parditka B, Erdélyi Z, Szilágyi IM
Fabrication of ZnO–Al2O3 inverse opals with atomic layer deposited amorphous-Al2O3 for enhanced photocatalysis
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING 183: 108733. (2024) Full text
Lemago HH, Addin FS, Karajz DA, Igricz T, Parditka B, Erdélyi Z, Hessz D, Szilágyi IM
Synthesis of TiO2/Al2O3 double-layer inverse opal by thermal and plasma-assisted atomic layer deposition for photocatalytic applications
NANOMATERIALS 13:(8) Paper 1314. (2023) Full text
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Thin-film optics, ellipsometry and interface modification
My recent work also includes the optical characterization and modelling of thin films and multilayers. Spectroscopic ellipsometry is used to determine film thicknesses, optical constants and interfacial or roughness layers. This is particularly important for ALD-grown oxides and multilayered ZnO-, TiO2– and metal-containing structures, where the optical response is strongly influenced by thickness, morphology, interfaces and layer sequence.
A related direction concerns electron irradiation induced interface modification and interface-induced diffusion in oxide/semiconductor systems. These studies connect nanoscale defect generation, diffusion, optical characterization and interface patterning.
Gurbán S, Petrik P, Serényi M, Sulyok A, Menyhárd M, Baradács E, Parditka B, Cserháti C, Langer GA, Erdélyi Z
Electron irradiation induced amorphous SiO2 formation at metal oxide/Si interface at room temperature; electron beam writing on interfaces
SCIENTIFIC REPORTS 8: Paper 2124. (2018) Full text
Gurbán S, Sulyok A, Menyhárd M, Baradács E, Parditka B, Cserháti C, Langer GA, Erdélyi Z
Interface induced diffusion
SCIENTIFIC REPORTS 11: Paper 9308. (2021) Full text
Fouad SS, Atyia HE, Baradács E, Erdélyi Z, Mehta N
Synthesis of multiple layers of alternating ZnO and TiO2 using atomic layer deposition and their optical characterization
OPTICAL MATERIALS 151: 115368. (2024) Full text
Fouad SS, Nabil M, Sharma AK, Mehta N, Erdélyi Z
Linearization and characterization of the Wemple–DiDomenico model of ZnO/Ni/ZnO tri-layer thin films prepared by ALD and DC magnetron sputtering
JOURNAL OF ALLOYS AND COMPOUNDS 990: 174348. (2024) Full text
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Metal-air batteries and sustainable electrochemical energy storage
In collaboration with the Kéki group, I am also involved in research on environmentally friendly metal-air batteries and electrochemical energy storage systems. These studies combine materials science, surface characterization, polymer chemistry and electrochemistry, with special attention to low-cost, heavy-metal-free and partly biodegradable battery components.
This research line includes Zn-air rechargeable batteries with charcoal-based cathodes, cellulose-derivative-based 3D-printed prototypes, brass-derived zinc anodes for dendrite-free operation, and recent Li-air battery systems using cotton and charcoal cathodes.
Nagy T, Nagy L, Erdélyi Z, Baradács E, Deák G, Zsuga M, Kéki S
Environmentally friendly Zn-air rechargeable battery with heavy metal free charcoal based air cathode
ELECTROCHIMICA ACTA 368: 137592. (2021) Full text
Nagy T, Nagy L, Erdélyi Z, Baradács E, Deák G, Zsuga M, Kéki S
Environmentally friendly high performance Zn-air rechargeable battery using cellulose derivatives: A 3D-printed prototype
JOURNAL OF ENERGY STORAGE 49: 104173. (2022) Full text
Nagy T, Nagy L, Erdélyi Z, Baradács E, Deák G, Zsuga M, Kéki S
“In Situ” Formation of Zn Anode from Bimetallic Cu-Zn Alloy (Brass) for Dendrite-Free Operation of Zn-Air Rechargeable Battery
BATTERIES 8:(11) Paper 212. (2022) Full text
Nagy L, Üneri HS, Kordován MÁ, Nagy T, Kuki Á, Nyul D, Pál P, Erdélyi Z, Zsuga M, Kéki S
Organic Solvent-Based Li-Air Batteries with Cotton and Charcoal Cathode
JOURNAL OF THE ELECTROCHEMICAL SOCIETY 171:(4) Paper 040509. (2024) Full text
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Interface engineering, barrier coatings and applied nanomaterials
A further application-oriented part of my research deals with interface engineering and protective coatings. This includes ALD-grown barrier layers on polymer substrates, the mechanical and structural stability of thin oxide films, and the role of defects, additives and interfacial segregation in determining film performance.
These studies are motivated by both fundamental and technological questions: how ultrathin coatings fail, how interfaces can be stabilized, and how nanoscale structural changes influence macroscopic properties such as permeability, adhesion, optical response and durability.
Tomán J, Baradács E, Vecsei G, Nagy L, Parditka B, Kéki S, Erdélyi Z
Low-temperature, ultra-giant blistering of atomic layer deposited barrier coatings on polyethylene films caused by additive segregation
PROGRESS IN ORGANIC COATINGS 204: 109261. (2025) Full text
Gulyás S, Katona G, Csiszár G, Tomán J, Cserháti C, Erdélyi Z
The effect of self-organization during deposition on the segregation behaviour of Au in the Si-Ge-Au nano-multilayer thermoelectric generator system
MATERIALS CHARACTERIZATION 209: 113699. (2024) Full text
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For a complete and regularly updated list of publications, please visit my publications page, my MTMT profile, or my Google Scholar profile.
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Excellent study. I am exploring the mechanism of diffusion about Al and SiO2. So i am very interested in your work!