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SELECTIVE EMITOR FOR THERMOPHOTOVOLTAIC SYSTEMS
Šimonová, Lucie ; Hrzina,, Pavel (referee) ; Šály,, Vladimír (referee) ; Vaněk, Jiří (advisor)
The work is focused on research and development of a suitable method for creating a selective emitter for the visible and near infrared region so that they are able to work optimally together with silicon photovoltaic cells in a thermophotovoltaic system. The aim of the work was to develop a new method of creating very fine structures outside the current standard, which will increase the emissivity of the base material to meet the needs of a selective emitter for the VID and NIR region. The methods available to us for the creation of structures were chosen, from which we eliminated all unsuitable ones and we introduced the optimal procedure and parameters for their creation for the selected method. In this work, we focused on both ceramic and metallic materials, whose heat resistance and selective properties are key to this work. Part of the development of the emitter structures was also the need for pretreatment of the substrate itself, where great emphasis was placed on the purity of materials and surface roughness. Since ceramic materials cannot achieve a surface roughness so low that the desired structures can be formed, these materials have been purposefully used primarily for the purpose of combining the base material with thin layers of other high temperature material. Their compatibility and suitability were verified in terms of adhesion and subsequent heat resistance. The main material for the formation of fine structures was purposefully chosen tungsten, for which we verified the influence of the formed structure on the emissivity as well as the thermal stability during long-term exposure to high temperatures. The work thus represents not only a new method of creating very fine structures, which are not normally formed in such subtlety, but also opens the way to new possibilities of combining more materials to achieve the required selectivity of the thermophotovoltaic emitter.
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Analysis and characterisation of spirally-arranged field-emission nanostructure
Ondříšková, Martina ; Sobola, Dinara (referee) ; Knápek, Alexandr (advisor)
Katody obsahující pole emitorů s vysokým poměrem stran budí velký zájem jako elektronové zdroje pro vakuová zařízení. Ve snaze maximalizovat proud a proudovou hustotu byly navrženy hustší pole emitorů. To však vedlo k nežádoucím účinkům, jako je stínění pole, způsobené přítomností okolních emitorů v poli. Pro snížení efektu stínění, a tím pádem zvýšení proudové hustoty, bylo navrženo pole emitorů s uspořádáním inspirovaným přírodním principem fylotaxe. Takto navržená struktura mikropilířů byla vytvořena pomocí elektronové litografie a reaktivního iontového leptání. K vytvoření ultra ostrých hrotů s poloměrem v řádu desítek nanometrů na vrcholu každého mikropilíře byla použita technika leptání black siliconu. Analýza topografie vzorku byla provedena pomocí rastrovacího elektronového mikroskopu. Pro stanovení výstupní práce byla použita ultrafialová fotoelektronová spektroskopie. Pro zjištění emisních vlastností vyrobených struktur byl zkonstruován emisní mikroskop, jehož elektronové dělo bylo upraveno tak, aby vyrobená struktura sloužila jako katoda. Graf Murphy-Good byl použit k analýze dat o emisních vlastnostech, na které byl aplikován ortodoxní test pro kontrolu validity. Pro sledování fluktuací proudu bylo provedeno měření stability.
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Mechanical design of measurement system for reactive ion etching system
Maňka, Tadeáš ; Antoš, Martin (referee) ; Šerý, Mojmír (advisor)
The aim of this work is to design fully working measuring system for the reactive ion etching system (RIE). The Michelson interfometer, previously developed in Ústav přístrojové techniky, v.v.i., is used in this work. The theoretical part is aimed at description of interferometric methods for precise measuring of length. In next part the etching proces with RIE is described. In practical part the testing system was constructed from the parts of Thorlabs company . The functionality was controlled with this system and the results of measuring were compared with the profilometer. In next step technical drawings were created and the whole system was made.
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Analysis and characterisation of spirally-arranged field-emission nanostructure
Ondříšková, Martina ; Sobola, Dinara (referee) ; Knápek, Alexandr (advisor)
Katody obsahující pole emitorů s vysokým poměrem stran budí velký zájem jako elektronové zdroje pro vakuová zařízení. Ve snaze maximalizovat proud a proudovou hustotu byly navrženy hustší pole emitorů. To však vedlo k nežádoucím účinkům, jako je stínění pole, způsobené přítomností okolních emitorů v poli. Pro snížení efektu stínění, a tím pádem zvýšení proudové hustoty, bylo navrženo pole emitorů s uspořádáním inspirovaným přírodním principem fylotaxe. Takto navržená struktura mikropilířů byla vytvořena pomocí elektronové litografie a reaktivního iontového leptání. K vytvoření ultra ostrých hrotů s poloměrem v řádu desítek nanometrů na vrcholu každého mikropilíře byla použita technika leptání black siliconu. Analýza topografie vzorku byla provedena pomocí rastrovacího elektronového mikroskopu. Pro stanovení výstupní práce byla použita ultrafialová fotoelektronová spektroskopie. Pro zjištění emisních vlastností vyrobených struktur byl zkonstruován emisní mikroskop, jehož elektronové dělo bylo upraveno tak, aby vyrobená struktura sloužila jako katoda. Graf Murphy-Good byl použit k analýze dat o emisních vlastnostech, na které byl aplikován ortodoxní test pro kontrolu validity. Pro sledování fluktuací proudu bylo provedeno měření stability.
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SELECTIVE EMITOR FOR THERMOPHOTOVOLTAIC SYSTEMS
Šimonová, Lucie ; Hrzina,, Pavel (referee) ; Šály,, Vladimír (referee) ; Vaněk, Jiří (advisor)
The work is focused on research and development of a suitable method for creating a selective emitter for the visible and near infrared region so that they are able to work optimally together with silicon photovoltaic cells in a thermophotovoltaic system. The aim of the work was to develop a new method of creating very fine structures outside the current standard, which will increase the emissivity of the base material to meet the needs of a selective emitter for the VID and NIR region. The methods available to us for the creation of structures were chosen, from which we eliminated all unsuitable ones and we introduced the optimal procedure and parameters for their creation for the selected method. In this work, we focused on both ceramic and metallic materials, whose heat resistance and selective properties are key to this work. Part of the development of the emitter structures was also the need for pretreatment of the substrate itself, where great emphasis was placed on the purity of materials and surface roughness. Since ceramic materials cannot achieve a surface roughness so low that the desired structures can be formed, these materials have been purposefully used primarily for the purpose of combining the base material with thin layers of other high temperature material. Their compatibility and suitability were verified in terms of adhesion and subsequent heat resistance. The main material for the formation of fine structures was purposefully chosen tungsten, for which we verified the influence of the formed structure on the emissivity as well as the thermal stability during long-term exposure to high temperatures. The work thus represents not only a new method of creating very fine structures, which are not normally formed in such subtlety, but also opens the way to new possibilities of combining more materials to achieve the required selectivity of the thermophotovoltaic emitter.
|
|
| |
|
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Mechanical design of measurement system for reactive ion etching system
Maňka, Tadeáš ; Antoš, Martin (referee) ; Šerý, Mojmír (advisor)
The aim of this work is to design fully working measuring system for the reactive ion etching system (RIE). The Michelson interfometer, previously developed in Ústav přístrojové techniky, v.v.i., is used in this work. The theoretical part is aimed at description of interferometric methods for precise measuring of length. In next part the etching proces with RIE is described. In practical part the testing system was constructed from the parts of Thorlabs company . The functionality was controlled with this system and the results of measuring were compared with the profilometer. In next step technical drawings were created and the whole system was made.
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