Projects

National

Kritické aspekty rastu polovodičových štruktúr pre novú generáciu III-N súčiastok
Critical aspects of the growth for a new generation of III-N devices
Program: VEGA
Project leader: Ing. Kuzmík Ján, DrSc.
Annotation: Gallium Nitride (GaN) compounds are investigated for a new generation of high-frequency transistors, powerelectronics and post CMOS logic circuits. Flexibility in this area is given by a miscibility of In and Al with GaN,providing a wide spectra of semiconductors with a possibility of setting an energy band-gap from 0.65 eV to 6.2eV, with countless combinations of heterostructures. Basis of our project is given by study and mastering of thegrowth of unique material concepts using a metal-organic chemical-vapour deposition (MOCVD) technique. Weaim to investigate: i/ transistors with N-polar InN channel, ii/ MOS contacts on N-polar heterostructures, iii/transistors with a hole conduction, as well as iv/ vertical structures on GaN substrate. Part of the project will berepresented by characterisation activities, like investigation of the electron transport properties in N-polar InN, in MOS structures, study on the 2-dimensional hole gas as well as transient effect in C-doped vertical transistors.
Duration: 1.1.2022 – 31.12.2025
Moderné elektronické súčiastky na báze ultraširokopásmového polovodiča Ga2O3 pre budúce vysokonapäťové aplikácie
Modern electronic devices based on ultrawide bandgap semiconducting Ga2O3 for future high-voltage applications
Program: SRDA
Project leader: Ing. Gucmann Filip, PhD.
Annotation: Wide bandgap (WBG) semiconductor devices represent one of the key technologies in development of high power and high frequency systems for electric power conversion and telecommunications owing to their fundamental benefit of higher breakdown electric fields, in some cases increased electron mobility, and possibility to form heterostructures and 2D electron gas. GaN and SiC, two typical WBG examples also benefit from moderate values of thermal conductivity allowing for more efficient sinking of generated waste heat, lower channel temperatures, and enhanced device reliability. New emerging semiconductor materials with even higher bandgap energies (Eg>3.4eV) referred to as ultrawide bandgap materials allow for further improvements in high power and high voltage handling solid-state electronic devices. Currently, semiconducting gallium oxide (Ga2O3) is under extensive study and expected to provide base material for rectifying Schottky -gate diodes and field-effect transistors for applications operating in kV range thanks to its good scalability, relatively simple synthesis, availability of native melt-grown substrates, and wide range of achievable n-type doping levels. The main aim of the proposed project constitutes material research and development of technology for epitaxial growth of epitaxial α -,β-, and ε-Ga2O3 layers and for processing of basic unipolar and bipolar electronic devices based on prepared Ga2O3 layers for future high voltage/power applications. Ga2O3 layers will be grown using liquid injection metalorganic chemical vapour deposition on sapphire, and higher thermal conductivity SiC substrates. We also aim to prepare Schottky diodes, FETs, and all-oxide Ga2O3 PN diodes using naturally p-type oxides (e.g. NiO, In2O3, CuO2). Comprehensive structural, electrical, optical, and thermal study of prepared epitaxial layers and devices will be conducted and numerous original, high-impact results are expected to be obtained.
Duration: 1.7.2021 – 30.6.2025
PEGANEL – p-GaN elektronika pre úsporu energie a post-CMOS obvody
p-GaN electronics for energy savings and beyond-CMOS circuits
Program: SRDA
Project leader: Ing. Kuzmík Ján, DrSc.
Annotation: III-N semiconductors are probably the most versatile and promising semiconductor family, consisted of artificialcompounds made of GaN, AlN and InN. In the project proposal we describe new technological concepts withsufficient freedom to solve main problems of the III-N post-beyond CMOS age: in transistors co-existence of theparasitic n-channel along with the p-channel, as well as low hole gas density and mobility. Similarly, we aim todemonstrate scalable threshold voltage in the enhancement-mode p-doped power transistors, which are needed bythe industry for efficient, energy-saving convertors. In these aspects, our laboratories already showed verypromising results proving the competence to reach described targets. If successfully implemented, results of ourproposed project would represent a significant step forward not only from the world-wide point of view but is also infull agreement with the RIS3 SK (perspective areas of specialization of the Slovak economy), particularly in thefield of semiconductors for electric cars of automotive industry, as well as in information and communicationsciences.
Duration: 1.7.2022 – 30.6.2025
Vysokovýkonná zakrivená röntgenová optika pripravená pokročilou technológiou nanoobrábania
High-performance curved X-ray optics prepared by advanced nanomachining technology
Program: VEGA
Project leader: Ing. Zápražný Zdenko, PhD.
Annotation: The project is focused on the research and development of new types of X-ray optics with highly accurate curvedactive surfaces. The surfaces will be prepared by an innovative nanomachining technology. We will investigatethe application of nanomachining technology to a special case of X-ray optics with curved surfaces, which is aparabolic refractive lens operating in the transmission geometry. The second special case we will focus on will bethin crystal monochromators with different thicknesses in a range of 20-2000 micrometers. Such elements can beused for example as beam splitters in modern X-ray free-electron lasers (XFEL), bent crystals in Johanssonmonochromators for spectroscopic applications, or they can also be used in particle accelerators for beamsteering. The developed elements of curved X-ray optics will be tested in real X-ray metrology and X-ray imagingexperiments using laboratory or synchrotron X-ray sources and highly sensitive directly converting X-raydetectors Pilatus and Medipix.
Duration: 1.1.2021 – 31.12.2023
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