National Repository of Grey Literature 3 records found  Search took 0.00 seconds. 
Mechanical and Electrical Properties of Microcrystalline Silicon Thin Films
Vetushka, Aliaksei ; Fejfar, Antonín (advisor) ; Čech, Vladimír (referee) ; Sládek, Petr (referee)
Amorphous and nano- or micro- crystalline silicon thin films are intensively studied materials for photovoltaic applications. The films are used as intrinsic layer (absorber) in p-i-n solar cells. As opposed to crystalline silicon solar cells, the thin films contain about hundred times less silicon and can be deposited at much lower temperatures (typically around 200 0 C) which saves energy needed for production and makes it possible to use various low cost (even flexible) substrates. However, these films have a complex microstructure, which makes it difficult to measure and describe the electronic transport of the photogenerated carriers. Yet, the understanding of the structure and electronic properties of the material at nanoscale is essential on the way to improve the efficiency solar cells. One of the main aims of this work is the study of the structure and mechanical properties of the mixed phase silicon thin films of various thicknesses and structures. The key parameter of microcrystalline silicon is the crystallinity, i.e., the microcrys- talline volume fraction. It determines internal structure of the films which, in turn, decides about many other properties, including charge transport and mechanical sta- bility. Raman microspectroscopy is a fast and non-destructive method for probing the...
Design of Low-Temperature Ultra High Vacuum Scanning Probe Microscopes
Pavera, Michal ; Klapetek, Petr (referee) ; Vetushka, Aliaksei (referee) ; Šikola, Tomáš (advisor)
This thesis deals with the development of scanning probe microscopes. Mechanical requirements for microscopes using measuring methods of scanning tunneling microscopy (STM) and atomic force microscopy (AFM) under enviroments of an ultrahigh vacuum (UHV) and variable temperatures are specified. Mechanical designs of two microscopes are discussed and their control electronics described. A special chapter is devoted to description of linear piezo manipulators and mechanical design of these prototypes.
Optical setup for torque detected electron spin resonance spectroscopy
Kern, Michal ; Vetushka, Aliaksei (referee) ; Neugebauer, Petr (advisor)
Táto diplomová práca sa venuje vylepšeniu spektroskopu Torzne Detegovanej Elektrónovej Spinovej Rezonancie (TDESR) výmenou aktuálnej kapacitnej detekcie výchylky ohybného ramienka za optické metódy. Práca popisuje základy Elektrónovej Spinovej Rezonančnej (ESR) spektroskopie s dôrazom na TDESR a tému magnetizmu jednomolekulových magnetov. Následne je vysvetlená detekcia výchylky ramienka pomocou odrazu laserového zväzku a interferometrie. Všetky kroky nutné k skonštruovaniu spektrometra a jeho uvedenia do prevádzky sú podrobne popísané. Pomocou detekcie odrazu laserového zväzku sme úspešne získali vysoko kvalitné TDESR spektrá kryštálu jednomolekulového magnetu Fe4. Týmto meraním sme dokázali vhodnosť použitia tejto metódy a jej výraznú prevahu nad pôvodnou kapacitnou detekciou, najmä v oblasti kvality, rozlíšenia a rýchlosti. Zároveň sme na ďaľšie vylepšenie TDESR spektrometra navrhli a zostrojili zostavu využívajúcu na detekciu výchylky interferometer.

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