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In-situ electron microscopy
Bukvišová, Kristýna ; Wandrol, Petr (referee) ; Kolíbal, Miroslav (advisor)
Cílem diplomové práce je popsat oxidaci nanotrubic sulfidu wolframičitého za zvýšených teplot v přítomnosti vodní páry. Na jejich povrchu se nejprve vytvoří nanočástice oxidu wolframu, ze kterých potom vyrůstají nanodráty. Na základě in-situ experimentů v rastrovacím elektronovém mikroskopu je navržen mechanismus reakce a ten je zjednodušeně popsán analyticky. Ukazuje se, že elektronový svazek má zásadní vliv na reakci.
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Photoluminiscence study of thin layers of MoS2
Kuba, Jakub ; Kunc,, Jan (referee) ; Bartoš, Miroslav (advisor)
The thesis deals with study of thin layers of transition metal dichalcogenides, especially of molybdenum disulfide. Nanostructures were fabricated on two-dimensional crystals of MoS2 and WSe2. Within followed analysis attention was paid to the photoluminescence properties. In the thesis transition metal dichalcogenides are reviewed and description of the modified process of preparation by micromechanical exfoliation is given.
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Application of two-dimensional layers of transition metal dichalcogenides in plasmonics
Kocourková, Monika ; Hrtoň, Martin (referee) ; Kvapil, Michal (advisor)
Two-dimensional layers of transition metal dichalcogenides are materials with some very intriguing properties, such as the existence of room-temperature stable excitons in visible and near-IR spectrum. Their integration into plasmonic systems allows enhancement of their photoluminescence, absorption, etc., which can be used in various applications. This thesis begins with an overview of the basic terminology and fundametal principles behind these materials and hybrid systems. The theoretical part then focuses on some plasmon-excitonic system examples. Practical part of this thesis is aimed at simulating and optimizing two different plasmon-excitonic systems using monolayer molybdenum disulphide and tungsten disulphide.
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Technological challenges in the fabrication of MoS.sub.2./sub./diamond heterostructures
Varga, Marián ; Sojková, M. ; Hrdá, J. ; Hutar, P. ; Parsa Saeb, S. ; Vanko, G. ; Pribusova Slusna, L. ; Ondič, Lukáš ; Fait, Jan ; Kromka, Alexander ; Hulman, M.
Nowadays, 2D materials are one of the most studied classes of materials. In addition to the most famous graphene, progress has been achieved in studying and using fundamental properties of transition metal dichalcogenides (TMD). Complementary, diamond as a representative of 3D materials has gained a reputation as an extremely versatile material due to its extraordinary combination of physical/chemical/electrical/optical properties. Besides these particular forms of 2D and 3D materials, their heterostructures have become very attractive due to new phenomena and functions (bandgap engineering, enhanced charge transport, optical interaction, etc.). However, individual technological procedures are still minimally investigated and described. Here, we will demonstrate a proof-of-concept for the preparation of MoS2/diamond heterostructures, where two different strategies were employed: a) growth of MoS2 layers on diamond films, and b) growth of diamond films on Si/MoS2 substrates.
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Ab initio study of electronic structure of 2D materials
Pekár, Zdenko ; Nezval, David (referee) ; Černý, Miroslav (advisor)
This bachelor’s thesis begins with an overview of basic terminology and principles regarding transition metal dichalcogenides and density functional theory. The theoretical part then brings several examples of atomic configuration of such materials and aproximations for the exchange-correlation functional. The practical part focuses on computational simulation and optimization of cells for various phases of transition metal dichalcogenides and their combinations, and compares their properties to those found in scientific literature and also gathers new, so far untested information about these materials.
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In-situ microscopy in corrosive environment
Nedvěd, Matěj ; Velický, Matěj (referee) ; Kolíbal, Miroslav (advisor)
This diploma thesis focuses on in-situ electron microscopy and its application to monitoring the chemical reactions on the surfaces of nanomaterials. The possibilities offered by this technique are presented, and the existing solution of an in-situ scanning electron microscope used for experiments is described. The thesis introduces Janus two-dimensional materials based on transition metal dichalcogenides with a focus on their preparation. A detailed description follows regarding the preparation of thin layers of WSe2 material using mechanical exfoliation and experiments conducted using an in-situ microscope. These experiments involved annealing of WSe2 material in the presence of hydrogen sulfide (H2S) while simultaneously observing it with an electron microscope, aimed to facilitate the chalcogenide exchange in this material. The morphology, composition, and optical properties of the material were subsequently analyzed using Raman spectroscopy and photoelectron spectroscopy. Finally, an experiment resulting in the successful exchange of selenium in WSe2 for sulphur is presented.
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Application of two-dimensional layers of transition metal dichalcogenides in plasmonics
Kocourková, Monika ; Hrtoň, Martin (referee) ; Kvapil, Michal (advisor)
Two-dimensional layers of transition metal dichalcogenides are materials with some very intriguing properties, such as the existence of room-temperature stable excitons in visible and near-IR spectrum. Their integration into plasmonic systems allows enhancement of their photoluminescence, absorption, etc., which can be used in various applications. This thesis begins with an overview of the basic terminology and fundametal principles behind these materials and hybrid systems. The theoretical part then focuses on some plasmon-excitonic system examples. Practical part of this thesis is aimed at simulating and optimizing two different plasmon-excitonic systems using monolayer molybdenum disulphide and tungsten disulphide.
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In-situ electron microscopy
Bukvišová, Kristýna ; Wandrol, Petr (referee) ; Kolíbal, Miroslav (advisor)
Cílem diplomové práce je popsat oxidaci nanotrubic sulfidu wolframičitého za zvýšených teplot v přítomnosti vodní páry. Na jejich povrchu se nejprve vytvoří nanočástice oxidu wolframu, ze kterých potom vyrůstají nanodráty. Na základě in-situ experimentů v rastrovacím elektronovém mikroskopu je navržen mechanismus reakce a ten je zjednodušeně popsán analyticky. Ukazuje se, že elektronový svazek má zásadní vliv na reakci.
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Photoluminiscence study of thin layers of MoS2
Kuba, Jakub ; Kunc,, Jan (referee) ; Bartoš, Miroslav (advisor)
The thesis deals with study of thin layers of transition metal dichalcogenides, especially of molybdenum disulfide. Nanostructures were fabricated on two-dimensional crystals of MoS2 and WSe2. Within followed analysis attention was paid to the photoluminescence properties. In the thesis transition metal dichalcogenides are reviewed and description of the modified process of preparation by micromechanical exfoliation is given.
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