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Electron microscopy and spectroscopy in plasmonics
Horák, Michal ; Krenn, Joachim (oponent) ; Shegai, Timur (oponent) ; Šikola, Tomáš (vedoucí práce)
This thesis deals with electron and ion beam techniques for fabrication and characterization of plasmonic nanostructures. Analytical electron microscopy focusing on applications in the field of plasmonics is discussed. The emphasis is given to electron energy loss spectroscopy (EELS) and cathodoluminescence. Further, fabrication of plasmonic samples for transmission electron microscopy is introduced while the aim is put at focused ion beam lithography and at sample preparation using chemically synthesized particles in water solution. The main research results are divided into four parts. The first part covers a comparative study of plasmonic antennas fabricated by electron beam and focused ion beam lithography. While both techniques are suitable for the fabrication of plasmonic antennas, electron beam lithography shall be prioritized over focused ion beam lithography due to better quality of the resulting antennas and considerably stronger plasmonic response in EELS. Antennas fabricated by focused ion beam lithography have slightly dull edges, exhibit pronounced thickness fluctuation, and they are also strongly contaminated not only by organic contaminants, but also by residues of FIB milling including implanted milling ions and atoms of a titanium adhesion layer. In the second part, Babinet's principle of complementarity for plasmonic nanostructures is investigated on a set of gold disc-shaped antennas and complementary apertures in a gold layer with various diameters. The complementarity is confirmed for fundamental plasmon properties such as resonance energies, but differences rising from the limited validity of Babinet's principle are found, for example, for the spatial distribution of the near-field of plasmon polaritons. The third part summarizes a study of nanostructures with functional properties related to the local enhancement of electric and magnetic field. Bow-tie and diabolo plasmonic antennas, both in the form of particles and in the form of apertures, exhibit particularly strong local field enhancement. Our study identifies several modes of localized surface plasmons in these antennas and characterizes their properties including mode energy, near field electric and magnetic field distribution, and the qualitative distribution of charge nodes and current associated with electron gas oscillations. Next, we have studied mode energy tunability in near infrared and visible spectral regions and focused on Babinet's complementarity between direct and inverted antennas. The last part is focused on silver amalgam, which is a novel and very prospective plasmonic material. By changing the size of silver amalgam nanostructures their plasmon resonance can be tuned from ultraviolet through the whole visible to infrared region. As silver amalgam is well investigated in the field of electrochemistry, silver amalgam nanoparticles opens a possibility to combine plasmonics and electrochemistry together.
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Studium katodoluminiscence polysilanových kompozitů
Neděla, David ; Kuřitka, Ivo (oponent) ; Schauer,, Petr (vedoucí práce)
Pro katodoluminiscenční měření byly připraveny vzorky s tenkou vrstvou poly[methyl(fenyl)silylenu]. U těchto vzorků byla sledována závislost katodoluminiscence na teplotě. Byla měřena spektra emitovaného světla u vzorku zahřívaného postupně na teploty 20, 50, 75 ,100 a 125 °C. Dále byla sledována kinetika procesu regenerace poly[methyl(fenyl)silylenu], která probíhala za zvýšené teploty. Vzorky polysilylenu byly zobrazeny pomocí elektronového mikroskopu.
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Vývoj mikromanipulátoru pro rastrovací elektronový mikroskop
Palouda, Adam ; Dostál, Zbyněk (oponent) ; Nováček, Zdeněk (vedoucí práce)
Tato práce se zabývá vývojem mikromanipulátoru pro rastrovací elektronový mikroskop. Nejprve poskytuje shrnutí základních poznatků o elektronové mikroskopii zaměřené především na návrh a výrobu vakuových systémů pro mikroskopy. Shrnuje také možnosti využití 3D tisku při výrobě prototypů vakuových systémů. Poté přistupuje ksamotnému vývoji mikromanipulátoru, který umožní měření katodoluminiscence v rastrovacím elektronovém mikroskopu. Zařízení se skládá z průchodky, přes kterou je dovnitř mikroskopu přivedeno optické vlákno, a z přesného manipulátoru, který umožní konec optického vlákna namířit na vybrané místo na vzorku. Signál z optického vlákna je zpracováván ve fotonásobiči, pro který je v rámci této práce vytvořen kryt, nebo ve spektrofotometru. Součástí je také popis testů a měření prováděných v průběhu vývoje a následných opatření pro dosažení lepší funkčnosti a uživatelského komfortu.
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Electron microscopy and spectroscopy in plasmonics
Horák, Michal ; Krenn, Joachim (oponent) ; Shegai, Timur (oponent) ; Šikola, Tomáš (vedoucí práce)
This thesis deals with electron and ion beam techniques for fabrication and characterization of plasmonic nanostructures. Analytical electron microscopy focusing on applications in the field of plasmonics is discussed. The emphasis is given to electron energy loss spectroscopy (EELS) and cathodoluminescence. Further, fabrication of plasmonic samples for transmission electron microscopy is introduced while the aim is put at focused ion beam lithography and at sample preparation using chemically synthesized particles in water solution. The main research results are divided into four parts. The first part covers a comparative study of plasmonic antennas fabricated by electron beam and focused ion beam lithography. While both techniques are suitable for the fabrication of plasmonic antennas, electron beam lithography shall be prioritized over focused ion beam lithography due to better quality of the resulting antennas and considerably stronger plasmonic response in EELS. Antennas fabricated by focused ion beam lithography have slightly dull edges, exhibit pronounced thickness fluctuation, and they are also strongly contaminated not only by organic contaminants, but also by residues of FIB milling including implanted milling ions and atoms of a titanium adhesion layer. In the second part, Babinet's principle of complementarity for plasmonic nanostructures is investigated on a set of gold disc-shaped antennas and complementary apertures in a gold layer with various diameters. The complementarity is confirmed for fundamental plasmon properties such as resonance energies, but differences rising from the limited validity of Babinet's principle are found, for example, for the spatial distribution of the near-field of plasmon polaritons. The third part summarizes a study of nanostructures with functional properties related to the local enhancement of electric and magnetic field. Bow-tie and diabolo plasmonic antennas, both in the form of particles and in the form of apertures, exhibit particularly strong local field enhancement. Our study identifies several modes of localized surface plasmons in these antennas and characterizes their properties including mode energy, near field electric and magnetic field distribution, and the qualitative distribution of charge nodes and current associated with electron gas oscillations. Next, we have studied mode energy tunability in near infrared and visible spectral regions and focused on Babinet's complementarity between direct and inverted antennas. The last part is focused on silver amalgam, which is a novel and very prospective plasmonic material. By changing the size of silver amalgam nanostructures their plasmon resonance can be tuned from ultraviolet through the whole visible to infrared region. As silver amalgam is well investigated in the field of electrochemistry, silver amalgam nanoparticles opens a possibility to combine plasmonics and electrochemistry together.
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Studium katodoluminiscence polysilanových kompozitů
Neděla, David ; Kuřitka, Ivo (oponent) ; Schauer,, Petr (vedoucí práce)
Pro katodoluminiscenční měření byly připraveny vzorky s tenkou vrstvou poly[methyl(fenyl)silylenu]. U těchto vzorků byla sledována závislost katodoluminiscence na teplotě. Byla měřena spektra emitovaného světla u vzorku zahřívaného postupně na teploty 20, 50, 75 ,100 a 125 °C. Dále byla sledována kinetika procesu regenerace poly[methyl(fenyl)silylenu], která probíhala za zvýšené teploty. Vzorky polysilylenu byly zobrazeny pomocí elektronového mikroskopu.
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