Institute of Technical Physics and Materials Science (MFA)

The main tasks of the Institute of Technical Physics and Materials Science (MFA) are: research on nanometer scale functional materials exploring their physical, chemical and biological properties, as well as the exploitation of these properties in the development of integrated nano/microsystems, sensors, and non-destructive characterisation techniques. Important task of the MFA is the technical support of the SMEs and the university education, the utilisation of the research infrastructure for serving the needs of graduate and postgraduate education (TDK, BSc, MSc, and PhD) in the scheme of an open access laboratory.

MFA hosts 5 scientific departments and 2 groups:

Microtechnology Department (www.mems.hu, www.biomems.hu, www.nems.hu)

The main task of the Microtechnology Department is the multidisciplinary research on sensors, the realisation of functional nano- and microsensors based upon novel sensing principles, their validation and elaboration of the adequate processing technology.

• In the framework of the EU FP7 PIEZOMAT project tactile sensor matrix was developed from vertically standing piezoelectric ZnO single-crystalline nanowires by combining nano- and microtechnology processing. The device facilitates the registration of fingerprints in 3D, which offers a much higher resolution than the currently used methods.
• In the frame of the ENIAC INCITE project robot development is pursued to facilitate Minimal Invasive Surgery. In the laparoscope of heart-surgery robots MFA silicon 3D force-sensors are used for the feed-back of haptic information to the surgeon conducting the operation. The piezoresistive force-sensor developed at the Microtechnology Department was modified to fulfil the medical requirements, thereby the accuracy and safety of the operation could be substantially improved.
• In the frame of the Hungarian Brain Research Project infrared optical elements are integrated into Silicon based microprobes. Besides of classical neurophysiology the new device is able for infrared neural stimulation as well.
• In polymer based Lab-on-a-Chip systems the wetting properties of channel walls were investigated. A new method to tailor the wetting properties and thereby the hydrodynamic behaviour of microfluidic channels was elaborated. In cooperation with industrial partners an enhanced microfluidic system could be developed and realised in order to detect a selected biomarker from the analysis of a single drop of blood.
• Microfluidic systems for biomedical applications require the controlled separation of micro- and nanoparticles in the applied fluids. New hydrodynamic and magnetic separation methods are developed and experimentally verified in real conditions.
• A new Plasma Assisted Atomic Layer Deposition system PICOSAN R-200 was purchased and installed with the financial support of the Hungarian Academy of Sciences. The new equipment is able to deposit various types of oxide, nitride sulphide and metallic thin films controlled on atomic scale. This considerable improvement in the processing facility allows us to initiate new domestic and international scientific co-operations and projects in the field of materials science.

Photonics Department (www.ellipsometry.hu)

The objectives of the Photonics Department are (1) the preparation as well as the non-destructive and real time characterization of thin films on large surfaces, in photonic and complex structures; (2) development of optical and magnetic measurement methods for the improvement of sensitivity and for the broadening of the range of materials that can be investigated by these methods; (3) preparation and spectroscopic characterization of self-organized surface nanostructures; (4) in situ monitoring of solid-liquid interface processes for the understanding of the adsorption of complex biomolecules and for the optimization of thin film preparations for sensors. Some of the major results in 2016:

• A recently developed non-destructive method called Magnetic Adaptive Testing (MAT), which is based on systematic measurement of minor magnetic hysteresis loops, was applied for detection of local wall thinning in ferromagnetic plates. It was shown that even a relatively small, local modification of the sample thickness could be detected with adequate signal/noise ratio from the other side of the specimen. The measurements gave sufficient results also, if the investigated plate was covered by other plate(s).
• In a continuing cooperation with the GREMAN laboratory of the University of Tours, columnar meso-Porous Si (PSi) thin films and dense nanowire carpets (SiNW) were characterized by spectroscopic ellipsometry and by different reference methods. It has been shown that not only the thickness and the density, but also the type of structural anisotropy can be characterized using proper isotropic, anisotropic and depth-profiling effective medium models.
• In cooperation with the Fuel and Reactor Materials Department, the optical properties of Zr tubes were characterized for nuclear fuel cladding. A method was provided for the optical qualification of the surface properties for the tubes with small diameters.
• Low-molecular weight polyethylene glycol (PEG) was used to trigger the clustering of gold nanoparticles through the control of colloidal interactions. The clustering is attributed to the delicate interplay between the high ionic strength and elevated temperature and is interpreted in terms of chain collapse of the surface-grafted PEG molecules.
• By partial masking of the particles (using a spin-coated polymer layer) gold/silica Janus particles have been formed and studied using single-particle spectroscopy. It has been investigated, whether the ratio of coverage influences the single-particle spectra. The particles have also been characterized using correlative SEM images. The peak positions of the measured spectra shifted by 5-7 nm when changing the coverage between 33 and 50%.
• The department was involved in 2 EU-projects („SEA4KET” and ENIAC-2012-2 “E450DL”) to develop an imaging optical inspection device with a pinhole camera. Prototypes using a width of 30, 45-60 and 60-90 cm have been built. As a demonstration, thin oxide film-covered, NiSi-covered and plasma immersion ion implanted Si wafers were measured on a robotic arm in a clean room environment.

Nanobiosensorics “Lendület” Research Group (www.nanobiosensorics.com)

The Nanobiosensorics Group was established in 2012 in the framework of the “Lendület” programme of the Hungarian Academy of Sciences. The research profile of the group is the development and application of label-free optical biosensors, the mathematical modelling of the relevant biological, biophysical processes, development of protein-based functional coatings, and performing cell adhesion and signalization experiments.

• The group developed and tested a novel device in cooperation with Byosens GmbH and Corning Inc. The setup of the new appliance enables the integration into already applied laboratory tools (for example to incubators or to fluid injector systems), thus the application possibilities of the label-free detection can be significantly improved.
• The group developed a novel measuring setup in cooperation with the Ellipsometry Laboratory. With this innovation, it is possible to measure simultaneously on two different surfaces, among the same, in situ conditions. In the new setup, a flow-cell and the semi-cylindrical lens are applied together, using the Kretschmann geometry. Plasmon-enhanced ellipsometrical measurements with more internal reflections, wavelengths and incoupling angles were presented.
• They were the first, who produced coatings with wild-type and the RGD-displaying flagellin variants, which could influence cellular adhesion. The results showed that these proteins form dens monolayers on hydrophobic surfaces in a straightforward manner.
• It was demonstrated, that the flagellin protein can be put into polyelectrolite layers, and the formation of filaments can be induced by employing a suitable positively charged polyelectrolite.
• A novel method for calculating the exact number of proteins in the surface coatings was established. The method is very simple; it requires only a fluorescent microscope.
• Adhesion of primary human monocytes, in vitro differentiated macrophages and dendritic cells were measured by using the high-throughput Epic BenchTop label-free optical biosensor. By monitoring the spreading process, it was revealed that the adhesion of these immune cells does not follow obvious kinetics. The non-monotonic biosensor curves drew attention to the importance of kinetical monitoring: immune cells showed more complex adhesion behavior, than other already examined cancer cell types.
• A novel method was developed, which can isolate single cells automatically from suspension, without fixing the cells to the surface. A simple 3D printer was used to build a miniature „multi-wellplate” into Petri-dishes. This simple technique requires minimal sample preparation, and it is applicable for any cell types, even cells from tissues.

Department of Thin Film Physics (www.thinfilm.hu)

The research activity of Thin Film Physics Department is focusing closely to materials science and thin film physics. The traditional research fields are the development of the polycrystalline layers and structural formation of the semiconductor layers. The ion-solid interactions, ion mixing layers, interfaces, advanced ceramics and biocompatible implant development are important research subjects as well. The new research topic of the laboratory is a development of ceramic reinforced nanostructured ODS steel prepared by powder technology. The strength of laboratory is the structural investigation of different materials by transmission electron microscopy. The methodological developments based on electron diffraction methods support all research topics. Their results achieved in 2016 are the following:

• The main aim of JST-V4 research project is a development of MOS switching transistor based GaN technology, which are normally turned off, thus the conversion losses will be reduced. They obtained that alumina layers deposited at low temperature (100 °C) by ALD exhibit GaN/AlGaN/GaN crystalline structure, as well as the layer deposited at high temperature (600°C) by MOCVD.
• ZnO as 2D material was prepared by ALD (Atomic Layer Deposition) within the frame of FLAG_ERA project. The ZnO crystallites showed a continuous layer grown already after 30 growth cycles. A 2-5 nm thin silicon oxide layer was obtained between the crystallites and the substrate.
• MTA Postdoctoral Fellowship and bilateral scientific project between CNR and MTA provided the possibility to study the structural properties of Ga₂O₃ wide bandgap semiconducting oxide (~ 4.7 eV). The detailed TEM studies allowed to investigate the real structure of the as-deposited layers at 600°C and showed the orthorhombic structure with Pna21 space group symmetry, called κ-Ga₂O₃. The phase transformation into β-Ga₂O₃ polycrystalline structure with a texture was observed after heat treatment at 1000°C during 2h.
• The main aim of M-ERA.NET  project is the development of novel, highly efficient tribological systems on the basis of ceramic/graphene nanocomposites, to prove their superior quality, and to demonstrate their suitability for technical applications, e.g., for slide bearings and seals in aqueous media. Si₃N₄ composites with 1-10 wt% graphene addition were prepared by spark plasma sintering (SPS), hot pressing (HP) and hot isostatic pressing (HIP). It was shown that the sintering process affected the properties of composites.  The fully densified Si₃N₄/multilayered graphene composites were prepared by HP sintering. HIP process resulted in the composite with high hardness and SPS with good toughness.
• EU FP7 “HypOrth” Project helps understanding local adverse reactions around artificial joint replacements and to improve integration of potential hypoallergenic implants with improved biocompatibility. HypOrth has already developed bioactive implant surfaces including bioceramics. A very unique surface coating will be realized by using powder technology from eggshells and seashells as a source for calcium/ hydroxyapatite coating to enhance osseointegration and mimic biocompatibility. This technology has been proven to be efficient and effective in simulator tests.
• Multi-component or high-entropy alloys containing Fe, Ni, Co, Cu, Cr different metals in near-equimolar concentrations studied in the NN OTKA project. It was shown that the further addition of Nb results in the formation of two-component growth.  Increasing the Nb content the crystal growth is limited, the size of the cubic crystallites is decreased and finally an amorphous structure is formed.

Nanostructures Department and 2D Nanoelectronics “Lendület” Research Group (www.nanotechnology.hu)

The research efforts of the Nanostructures Department focused on 2D materials, ranging from their isolation, through atomic resolution characterization and nanofabrication, to investigating the novel properties of their nanostructures. Besides graphene the focus of attention continuously shifted towards 2D Transition Metal Dichalcogenides. Another important research topic of the Department was the investigation of bio inspired photonic nanoarchitectures.

• Within the “Lendület” Project, they were able to image directly for the first time the atomic scale oxidation of 2D MoS₂ crystals under ambient conditions. The atomic resolution STM measurements revealed that oxidation proceeds through individual atomic substitution of sulphur atoms by oxygen, while fully preserving the original crystal lattice.
• Within the NanoFab2D ERC Starting Grant, they have developed a novel device concept exploiting the magnetism at the zigzag edges of graphene nanoribbons enabling the control of both charge and spin signals within the simplest three-terminal field-effect transistor device configuration.
• In the framework of Korea-Hungary Joint Laboratory for Nanosciences they have experimentally observed a novel graphene super lattice of anomalously large periodicity. Molecular Dynamics simulations revealed a substantial distortion of the crystal lattice at the origin of the novel graphene superstructure.
• Within the EU FP7 Marie Curie project the department have quantitatively measured the interaction forces between the STM tip and a graphene sheet by combined STM and AFM investigations of suspended graphene membranes.
• Within the framework of two OTKA grants they demonstrated that pre-treatment of photonic nanoarchitectures on butterfly wings with organic solvents is suitable to tune the sensitivity of optical vapour sensors based on butterfly wing scales.

Complex Systems Department

The main theoretical results of the Complex Systems Research Group are achieved in the investigation of multiagent evolutionary games by using the methods of non-equilibrium statistical physics. Additionally they study different phenomena on networks and relationships between genetic data and folk song data basis.

• In the field of evolutionary games they have studied evolutionary mechanisms supporting the maintenance of cooperation among selfish individuals. Recently they have clarified the relevant role of those players who are connected to several influential players (hubs). The positive effect of the inhomogeneity in the level of tolerance is also demonstrated. In the evolutionary public goods games their analysis quantified the advantage of the evolving group structure.
• The systematic analysis of the spatial evolutionary potential games is based on the application of the concept of decomposition when the payoff matrices are built up from a set of elementary games classified into four types. This approach has indicated that the Ising type phase transition is preserved if the coordination between a strategy pair is extended by additional neutral strategies until their number is sufficiently low, otherwise first order transition occurs when the noise level is increased. Additionally they have explained the consequences of anisotropic invasion occurring for imitation of a better neighbour.
• The statistical physical studies of networks and dynamical processes on irregular graphs are extended to those connectivity structures which are deduced from the experimental investigations of human brain. The results support the introduction of more realistic networks in the numerical analyses.

The determination of the characteristic folk songs is improved by developing an algorithm allowing variations in the number of types, too. This algorithm has revealed quantitatively the coincidence of relatives extracted from data in genetics, folk song and archaeology.