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UV detection by Grafen/GaN structures
Kostka, Marek ; Piastek, Jakub (referee) ; Mach, Jindřich (advisor)
This bachelor thesis covers fabrication as well as the study of behavior of UV sensor based on galium nitride structures on graphene substrate. The sensor takes advantage of high mobility of charge carriers in graphene and UV selective sensitivity of GaN nanoctystals. This combination exhibits a potential for being a UV sensor because of the unique properties brought by both materials. The first part of this work describes graphene, galium nitride and graphene/GaN heterostructure with their properties and fabrication processes. The second part includes full description of already used fabrication process and characterization of the optical and electrical behavior using photoluminiscence and transport properties measurements.
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Mechanical excitation of self sensing SPM probes
Novotný, Ondřej ; Piastek, Jakub (referee) ; Pavera, Michal (advisor)
This bachelor thesis deals with the development of the SPM microscope probe holder which is designed for mechanical excitation of the probes. The first part of the thesis focuses on the description of physical theory, such as the principle of atomic force microscopy, the function of piezoceramics and the description of used quartz tunning fork based probes. The second part describes the gradual development and design of the new probe holder. Testing of the designed probe holder and comparison of mechanical and electric excitation is depicted at the end of this work. The designed probe holder was manufactured, the assembly procedure was described, and the drawings of the individual parts were created.
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GaN deposition on a tungsten substrate
Pikna, Štěpán ; Piastek, Jakub (referee) ; Čalkovský, Vojtěch (advisor)
This bachelor thesis is focused on deposition of GaN nanocrystals on the etched tungsten tips. Motivation was to prepare these GaN structures on the Schottky cathode made by company ThermoFisher Scientific and measure its field emission. In the theoretical part of the thesis GaN and tungsten field emission properties are introduced. The experimental part begins with tungsten tip etching optimalization, where the right values for best tips are temperature 20 °C, depth of the tip 2,5 mm and solution NaOH used. Further the gallium structures were prepared on these tips using molecular beam epitaxy (MBE). The right temperature to prepare GaN nanocrystals was determined as 200 °C. The deposition of gallium was set to 2 hours and following nitridation was 3 hours. Finally, the field emission from GaN prepared on copper foil with graphene was measured and compared with other experiments.
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GaN deposition on a tungsten substrate
Pikna, Štěpán ; Piastek, Jakub (referee) ; Čalkovský, Vojtěch (advisor)
This bachelor thesis is focused on deposition of GaN nanocrystals on the etched tungsten tips. Motivation was to prepare these GaN structures on the Schottky cathode made by company ThermoFisher Scientific and measure its field emission. In the theoretical part of the thesis GaN and tungsten field emission properties are introduced. The experimental part begins with tungsten tip etching optimalization, where the right values for best tips are temperature 20 °C, depth of the tip 2,5 mm and solution NaOH used. Further the gallium structures were prepared on these tips using molecular beam epitaxy (MBE). The right temperature to prepare GaN nanocrystals was determined as 200 °C. The deposition of gallium was set to 2 hours and following nitridation was 3 hours. Finally, the field emission from GaN prepared on copper foil with graphene was measured and compared with other experiments.
|
|
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UV detection by Grafen/GaN structures
Kostka, Marek ; Piastek, Jakub (referee) ; Mach, Jindřich (advisor)
This bachelor thesis covers fabrication as well as the study of behavior of UV sensor based on galium nitride structures on graphene substrate. The sensor takes advantage of high mobility of charge carriers in graphene and UV selective sensitivity of GaN nanoctystals. This combination exhibits a potential for being a UV sensor because of the unique properties brought by both materials. The first part of this work describes graphene, galium nitride and graphene/GaN heterostructure with their properties and fabrication processes. The second part includes full description of already used fabrication process and characterization of the optical and electrical behavior using photoluminiscence and transport properties measurements.
|
|
|
Mechanical excitation of self sensing SPM probes
Novotný, Ondřej ; Piastek, Jakub (referee) ; Pavera, Michal (advisor)
This bachelor thesis deals with the development of the SPM microscope probe holder which is designed for mechanical excitation of the probes. The first part of the thesis focuses on the description of physical theory, such as the principle of atomic force microscopy, the function of piezoceramics and the description of used quartz tunning fork based probes. The second part describes the gradual development and design of the new probe holder. Testing of the designed probe holder and comparison of mechanical and electric excitation is depicted at the end of this work. The designed probe holder was manufactured, the assembly procedure was described, and the drawings of the individual parts were created.
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