Projects

International

MSC – Vývoj vertikálnych kompozitov z dichalkogenidov prechodových kovov pre použitie v mikrosuperkondenzátoroch
Vertically aligned two-dimensional transition metal dichalcogenide composites for micro-supercapacitors
Program: Bilateral – other
Project leader: Dr. rer. nat. Hulman Martin
Duration: 1.1.2023 – 31.12.2025
Topologicky netriviálne fázy vrstvených dichalkogenidov prechodných kovov
Topologically nontrivial phases of layered transition-metal dichalcogenides
Program: Bilateral – other
Project leader: Dr. rer. nat. Hulman Martin
Duration: 1.1.2023 – 31.12.2024
Dichalkogenidy prechodových kovov s topologickými fázami: predikcie, syntéza a vlastnosti
Topological transition-metal dichalcogenides: prediction, synthesis and properties
Program: Bilateral – other
Project leader: Dr. rer. nat. Hulman Martin
Duration: 1.4.2021 – 31.12.2022
Príprava a charakterizácia veľmi tenkých vrstiev TMD materiálov na atomárnej škále
The preparation and atomic-scale characterization of ultrathin films of TMD materials
Program: Bilateral – other
Project leader: Dr. rer. nat. Hulman Martin
Duration: 1.4.2021 – 31.12.2022

National

ROTOLES – Optimalizovaný rast a transportné a optické vlastnosti tenkých vrstiev vybraných topologických polokovov
Optimised growth and the transport and optical properties of thin layers of selected topological semimetals
Program: SRDA
Project leader: Dr. rer. nat. Hulman Martin
Annotation: One of the fundamental results of quantum mechanics in the 1920s was the derivation of relativistic equations formassive fermions (Dirac), massless fermions (Weyl) and fermions that are themselves antiparticles (Majorana).Since those times, particle physics has been searching for particles representing Weyl and Majorana\’s fermions.However, their search has not yet been successful.In the last twenty years, it has been shown that the band structure of some materials has such uniquecharacteristics that the charge carriers in them can behave according to the dynamics satisfying the Dirac or Weylrelativistic equations. Such materials include compounds from the group of transition metals dichalcogenides,which we will focus on in our project.We will work with very thin layers of selected materials from this group, such as PtSe2, MoTe2 and WTe2. The firststep in the implementation of the project will be the preparation of such layers by chalcogenisation of thin films oftransition metals. Their transport and optical properties will then be thoroughly investigated. Temperaturedependent transport measurements can show us transitions between different structures of the same material. We expect that a metal-insulator transition can be observed when the thickness of such thin films is varied. Some ofthese materials can go into a superconducting state at very low temperatures. We will also try to induce this state inclose proximity, i.e. when the thin layer is in contact with another superconductor.Optical measurements will be correlated with transport measurements. We derive essential frequency-dependentcharacteristics, such as optical conductivity, from the latter. We will look for characteristics theoretically predictedfor Dirac and Weyl fermions in the optical conductivity.
Duration: 1.7.2024 – 30.6.2027
Transit2D – Tranzistory na báze 2D kovových chalkogenidov pripravených teplom podporovanou konverziou
Transistors based on 2D Metal Chalcogenides Grown via Thermally Assisted Conversion
Program: SRDA
Project leader: Ing. Ťapajna Milan, PhD.
Annotation: 2D materials can form one-atom-thick sheets with extraordinary properties. One of the most promising classes of2D materials is the transition metal dichalcogenides (TMDs). The transition from an indirect to a direct bandgap,when the bulk materials is thinned down to a monolayer, results in unique electrical and optical properties of 2DTMDs. Post-transition metal chalcogenides (PTMCs) represents another interesting group of 2D materials. Thesematerials have wide band gap and, depending on the structure of the material, show anisotropic electrical andoptical properties. The aim of this project is the fabrication of field-effect transistors with metal-oxide-semiconductorgate (MOSFETs) based on selected TMDs and PTMCs compounds and detail analysis of their transport properties.We will focus on large-area few-layer PtSe2 and GaS/GaSe films grown by thermal assisted conversion, i.e.sulfurization and selenization. Based on the existing experiences, structural, chemical and electrical properties ofhorizontally-aligned PtSe2 films prepared by selenization will be optimized, targeting mobilities similar to thoseprepared by mechanical exfoliation. Then, MOSFET technology using both, top-gate as well as bottom-gateapproach will be developed and optimized. Atomic layer deposition and metal-oxide chemical vapor deposition(MOCVD) will be employed for gate oxide growth. GaS/GaSe few-layer films will be prepared by chalcogenization
Duration: 1.7.2022 – 30.6.2026
Rast a optická charakterizácia 2D materiálov: MoTe2, WTe2, PtTe2
Growth and optical characterization of 2D materials: MoTe2, WTe2, PtTe2
Program: VEGA
Project leader: RNDr. Pribusová Slušná Lenka, PhD.
Annotation: Research of thin-film materials noticed a significant increase, especially since the discovery of graphene, when a wide range of 2D materials began to study. A significant group of 2D materials is transition metal dichalcogenides(TMDs), including MoTe2, WTe2, and PtTe2. These materials have unique optoelectronic properties that varydue to the thickness of the layer and the crystal structure. Electrical properties vary depending on structures, fromsemiconducting to metallic. The preparation of films by tellurization of molybdenum, tungsten, and platinum ismore difficult than sulfurization or selenization due to the weaker redox properties of tellurium. The challenge in thin films is the controlled preparation of the required crystal structure of homogenous large-arealayers. This project aims to contribute to the solution of preparing these materials, characterize their structure and orientation of the films concerning the substrate, and determine the optical parameters and electrical properties.
Duration: 1.1.2023 – 31.12.2025
Príprava, charakterizácia a dopovanie ultratenkých vrstiev dichalkogenidov prechodných kovov
Fabrication, characterization, and doping of ultra-thin layers of transition metal dichalcogenides
Program: VEGA
Project leader: Mgr. Sojková Michaela, PhD.
Annotation: Thanks to the unusual physical properties, 2D materials have been intensively studied for several years. Aninteresting group of this class of materials is transition metal dichalcogenides TMD. They have a hexagonalstructure with the individual layers bonded to each other only by weak Van der Waals bonds. This causessignificantly anisotropic properties and has a significant effect on their electronic structure. Some of them showphysically interesting correlated states (superconductivity, charge density waves). The primary goal of this projectis to prepare and study the properties of thin layers of 2 different TMD – MoS2 and PtSe2, and to study theinfluence of doping with Li and Na cations on the electrical and structural properties of these layers. Thesecondary goal is to optimize growth and doping conditions to improve the parameters of thin films, such aselectrical conductivity and charge carrier mobility which will enable the preparation of functional electroniccomponents – transistors.
Duration: 1.1.2021 – 31.12.2024
TMD2DCOR – Metalické 2D dichalkogenidy prechodných kovov: príprava, štúdium vlastností a korelované stavy
Fabrication, physics and correlated states in metallic 2D transition metal dichalcogenides
Program: SRDA
Project leader: Dr. rer. nat. Hulman Martin
Annotation: The discovery of graphene in 2004 has brought a massive interest of scientists active in condensed-matter physicson research of 2D materials. Even though these materials have a long history starting already in the twenties of the20th century, the past years have seen an intensive renascence of interest in 2D materials. Ultra-thin samples ofmany 2D materials have been successfully prepared with electronic properties that may exhibit correlatedelectronic phenomena such as charge density waves and superconductivity. One of the well-studied families of the2D materials are transition metal dichalcogenides (TMDs). TMDs consist of hexagonal layers of metal atomssandwiched between two layers of chalcogen atoms with a MX2 stoichiometry.In this project, we focus on those materials from the TMD family that exhibit strongly correlated electronic states:NbSe2, TiSe2, TaS2, TaSe2 and PtSe2. The goal of the project is to prepare ultrathin (≤ 10 nm) layers and bulksamples and characterise them thoroughly in terms of the thickness, crystallinity, homogeneity, optical andelectronic properties. A special attention will be paid to charge density wave states and superconductivity in thesematerials and how they evolve with the sample thickness, doping, external electric and magnetic fields and detailsof the growth process.The scientific program also aims at preparing heterostructures built up of these materials as well as hybrid systemscombining TMDs with other materials. This research also includes a detailed characterisation of heterostructures toprovide a feedback to optimise the growth process.
Duration: 1.7.2020 – 30.6.2023
Časovo-rozlíšené štúdium rastu hybridných van der Waalsových heteroštruktúr
Real-time grow studies of hybrid van der Waals heterostructures
Program: SRDA
Project leader: Dr. rer. nat. Hulman Martin
Duration: 1.8.2018 – 30.6.2022
Tribologické vlastnosti 2D materiálov a príbuzných nanokompozitov
Tribological properties of 2D materials and related nanocomposites
Program: SRDA
Project leader: Dr. rer. nat. Hulman Martin
Duration: 1.8.2018 – 30.6.2022
2DMOSES – 2D materiály iné ako grafén: monovrstvy, heteroštruktúry a hybridné vrstvy
2D materials beyond graphene: monolayers, heterostructures and hybrids
Program: SRDA
Project leader: Dr. rer. nat. Hulman Martin
Annotation: Two-dimensional (2D) materials have been one of the most extensively studied classes of materials due to their unusual physical properties. The best example is graphene – a single layer of carbon atoms arranged in a two dimensional (2D) honeycomb lattice. Many graphene´s extraordinary properties have been reported including excellent electronic and thermal conductivities and mechanical properties. Its discovery has also stimulated an extensive research on other 2D materials. It has been shown that it is not only possible to exfoliate stable, single-atom thick 2D materials, but that these materials can exhibit unique and fascinating physical properties. The 2D structure determines the electronic properties that may exhibit correlated electronic phenomena such as charge density waves and superconductivity. In this project, we focus on preparation of ultrathin (< 10 nm) films and monolayers of materials from the family of transition metal dichalcogenides (TMDs). The goal is to prepare those layers on a centimetre-large scale. For that, pulsed laser deposition and magnetron sputtering are the methods of our choice. As-prepared layers will then be thoroughly characterised in terms of their thickness, crystallinity, homogeneity, optical and electrical properties. As a next logical step, we will proceed in preparation of heterostructures and hybrids – systems where different TMDs materials and TMDs and graphene or graphene oxide are stacked on top of each other, respectively.
Duration: 1.7.2016 – 31.12.2019
Rast 2D materiálov: grafén a diselenid titánu
Growth of 2D materials: graphene and titanium diselenide
Program: VEGA
Project leader: Dr. rer. nat. Hulman Martin
Duration: 1.1.2015 – 31.12.2017