|
|
Techniques using beam of charged particles for imaging and material analysis
Lamborová, Leona ; Kičmerová, Dina (referee) ; Čupera, Jan (advisor)
This bachelor´s thesis deals with techniques using beam of charged particles for imaging and material analysis. There are two types of charged particles that are used for this purpose, electrons and ions. This research study is divided into principles of electron optics and principles of ion optics. Further, there is mentioned function, construction and detectors used for imaging and chemical analysis of scanning electron microscopy, transmission electron microscopy and focused ion beam.
|
|
|
Preparation and characterization of plasmonic graphene-copper nanostructures
Robešová, Magdaléna ; Pavelec,, Jiří (referee) ; Dvořák, Petr (advisor)
This diploma thesis deals with the study and preparation of graphene-copper nanostructures, which represent a new path in the research of plasmonic metasurfaces. This combination of copper with the unique properties of graphene could bring advancements in the quest for reliable copper plasmonic nanostructures. Alongside a literature review of previous scientific progress in this field, the nanostructures have been prepared using focused ion beam (FIB) and chemical vapor deposition (CVD) methods. Subsequently, the fabrication process underwent quality evaluation, and optical characterization was performed.
|
|
|
Integration of laser ablation into the workflows of FIB-SEM systems
Valenta, Jakub ; Adámek, Martin (referee) ; Búran, Martin (advisor)
Cílem této diplomové práce je ověření vlivu různých nastavení parametrů systému laserové ablace na různé typy mikroelektronických materiálů. Práce má za úkol popsat účel analýzy skrytých defektů v těchto strukturách a způsob jejich řešení. V rámci práce jsou řešeny principy funkce obráběcích a zobrazovacích zařízení na úrovni mikro- či nanometrových velikostí struktur. Předmětem zkoumání je především operační rozdíl mezi procesy obrábění pomocí iontového svazku a pomocí laserového paprsku a jeho integrace do oblasti zajištění kvality. Jde o propojení laserových zařízení se systémy iontových a~elektronových svazků. V práci jsou také popsány výsledky experimentů, během kterých byla provedena analýza defektů vybraných struktur.
|
|
|
Silicon Solar Cell Parameters Change After Focused Ion Beam Milling
Gajdos, Adam
Silicon is still one of the most used materials for fabrication of solar cells. Some imperfections and defects may appear during production process. These local imperfections could be eliminated by focused ion beam (FIB). Nevertheless, FIB milling process modifies the crystal structure of the material by ions implantation. Samples under investigation are monocrystalline silicon solar cells. The impact of FIB milling is shown and discussed through current-voltage measurement before and after milling process.
|
|
|
Techniques using beam of charged particles for imaging and material analysis
Lamborová, Leona ; Kičmerová, Dina (referee) ; Čupera, Jan (advisor)
This bachelor´s thesis deals with techniques using beam of charged particles for imaging and material analysis. There are two types of charged particles that are used for this purpose, electrons and ions. This research study is divided into principles of electron optics and principles of ion optics. Further, there is mentioned function, construction and detectors used for imaging and chemical analysis of scanning electron microscopy, transmission electron microscopy and focused ion beam.
|
|
|
Effect of ion beam irradiation and annealing on magnetic properties of FeRh nanostructures
Zadorozhnii, Oleksii ; Turčan, Igor (referee) ; Staňo, Michal (advisor)
Fazový přechod prvního řádu z antiferomagnetického do feromagnetického stavu v Fe50Rh50 z něj činí vhodný materiál pro nové generace spinových elektronických zařízení s nízkou spotřebou. Tato práce se zabývá způsoby, jak lze teplotu fázového přechodu železo-rhodia (FeRh) lokálně ovlivnit pomocí fokusovaneho iontového svazku (FIB) a žíhání. FIB byl zvolen vzhledem k tomu, že slitina FeRh vykazuje magnetickou citlivost na stupeň jejího chemického uspořádání, což je charakteristické pro všechny slitiny feromagnetických a neferomagnetických kovů. Tepelné žíhaní umožňuje obnovení krystalografického uspořádání, a uvolnění mřižkových defektů a dislokací. Magnetické vzory byly vyrobeny za použití FIB na bázi galia a žíhány ve vakuu. Topografie a magnetické chování těchto iontově ozářených vzorů byly zkoumány pomocí mikroskopie atomárních a magnetických sil při různých teplotách, a ukázaly jasnou závislost mezi dávkou iontového záření a magnetickou odezvou ve stavu před a po žíhání.
|
|
|
Optoelectrical characterization of well oriented n-type zno nanorod arrays on p-type GaN templates
Yatskiv, Roman ; Grym, Jan ; Schenk, Antonín ; Vaniš, Jan ; Roesel, David ; Chlupová, Šárka
A heterojunction formed between a single n-type ZnO nanorod and p-type GaN template was successfully prepared by low cost chemical bath deposition technique. Periodic circular patterns were fabricated by focused ion beam etching through poly(methyl methacrylate) mask to control the size, position, and periodicity of the ZnO nanorods. A possible growth mechanism is introduced to explain the growth process of the nanorods. Optical and electrical properties of the heterojunctions were investigated by low temperature photoluminescence spectroscopy and by the measurement of current-voltage (I-V) characteristics. The I-V characteristics were measured by directly contacting single ZnO nanorods with the conductive atomic force microscopy tip. The diode-like rectifying behavior was observed with a turn-on voltage of 2.3 V and the reverse breakdown voltage was 5 V
|
|
|
Growth of metastable fcc Fe thin films on Cu/Si(100) substrates
Horký, Michal ; Cháb, Vladimír (referee) ; Urbánek, Michal (advisor)
This diploma thesis deals with the preparation of epitaxially grown metastable paramagnetic Fe films alloyed by Ni on Cu/Si(100) substrates at RT. Molecular beam epitaxy of Cu(100) buffer layer was performed on H-Si(100) native SiO2 free samples treated by etching in HF or thermal treatment. The epitaxially grown Cu layers with thickness ranging from 50 up to 130 nm serves as suitable substrate for the deposition of 44-ML-thick paramagnetic Fe78Ni22. The film growth was taking place in CO atmosphere and as well as Ni it led to paramagnetic film stabilization. The structural and magnetic ion-beam-induced transformation of desired Fe-Ni structure was performed and propeties of irradiated films were characterized afterwards by MOKE. Then some specific patterns on Si(100) by e-beam litography were fabricated and they served as suitable matrix for Cu(100) buffer layer and paramagnetic Fe. Prepared Si(100), globally and locally deposited metal films were examined by LEED, XPS, AFM, AES, SEM a STM. The recorded results showed the possibility of paramagnetic films preparation on H-Si(100) where it was possible to make ferromagnetic patterns on paramagnetic background by irradiation of specific ion dose.
|
|
|
Magnetic properties of materials based on metastable Fe-Ni thin films
Křižáková, Viola ; Uhlíř, Vojtěch (referee) ; Flajšman, Lukáš (advisor)
Metastable Fe78Ni22 thin films grown on Cu(100) substrates are known for their capability of structural and magnetic phase transition upon ion beam irradiation. This thesis focuses on characterization of magnetic properties of FeNi layers with the emphasis on their anisotropic behaviour. An analytical model describing magnetic anisotropies, in planar structures and thin films, and its modification for Fe78Ni22/Cu(100) system is described in the theoretical part. In the experimental part, the anisotropy of ion-beam-transformed FeNi structures is thoroughly studied. The transformed films and patterns exhibit four-fold magnetic anisotropy originating from bcc iron crystal structure. Further, the possibility of modification of the magnetic anisotropy type by selecting a proper focused ion beam scanning strategy during the transformation is demonstrated. In the last part of the thesis, the maximum achievable lateral resolution of focused ion beam transformed structures is explored and a prototypical magnonic crystal is prepared.
|
|
|
Application onf the Focused Ion on Electron Beam in Nanotechnologies
Šamořil, Tomáš ; Mikulík, Petr (referee) ; Jiruše, Jaroslav (referee) ; Šikola, Tomáš (advisor)
Nowadays, the systems that allow simultaneous employment of both focused electron and ion beams are very important tools in the field of micro- and nanotechnology. In addition to imaging and analysis, they can be used for lithography, which is applied for preparation of structures with required shapes and dimensions at the micrometer and nanometer scale. The first part of the thesis deals with one lithographic method – focused electron or ion beam induced deposition, for which a suitable adjustment of exposition parameters is searched and quality of deposited metal structures in terms of shape and elemental composition studied. Subsequently, attention is paid also to other types of lithographic methods (electron or ion beam lithography), which are applied in preparation of etching masks for the subsequent selective wet etching of silicon single crystals. In addition to optimization of mentioned techniques, the application of etched silicon surfaces for, e.g., selective growth of metal structures has been studied. The last part of the thesis is focused on functional properties of selected 2D or 3D structures.
|
guest ::
