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Design and fabrication of interference filters for optical fibers
Švábík, Marek ; Liška, Jiří (referee) ; Konečný, Martin (advisor)
This bachelor's thesis is focused on the design and fabrication of interference filters that can be mounted on the ends of optical fibers. The thesis discusses the production process from the filter design to its fabrication by depositing thin layers on a Si wafer. Subsequently, it describes a design that allows the filter to be mounted on the end of an optical fiber and the manufacturing method of such a mountable cap. The fabrication itself involved etching the wafer. After mounting, the functionality of the manufactured filter was tested by measuring its transmittance.
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Optoelectronic characterization of perovskite materials and their application in photovoltaics
Ulč, Filip ; Konečný, Martin (referee) ; Klok, Pavel (advisor)
This bachelor's thesis is focused on a detailed correlative study of optoelectronic perovskite materials through advanced measurement techniques employed at the Institute of Physical Engineering. These techniques include surface charge measurement and time-resolved photoluminescence mapping. Currently, there are few publications or articles attempting to analyze optical and electrical processes using more than two techniques simultaneously. Therefore, the aim of this thesis is to expand the knowledge of existing techniques and enhance them by incorporating surface charge analysis (in the dark and under illumination) using Kelvin Probe Force Microscopy (KPFM). The contribution of this work to the study of perovskite materials lies in correlative measurements that provide new insights into the arrangement and movement of charge carriers, which can be utilized in the research of perovskite solar cells.
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Study of the stability of hydrogenated graphene
Dostál, Josef ; Švarc, Vojtěch (referee) ; Konečný, Martin (advisor)
This bachelor thesis deals with the study of the stability of hydrogenated graphene prepared by chemical vapour deposition and subsequently hydrogenated using an atomic hydrogen source. The hydrogenated graphene is then subjected to thermal annealing, UV irradiation and electron beam. The resistance of the hydrogenated graphene to these treatments is subsequently monitored by Raman spectroscopy. During the thermal annealing, partial dehydrogenation of the hydrogenated graphene was observed, whereas no dehydrogenation was observed for the other two methods. Only gradual degradation of hydrogenated graphene was observed for these two methods. In the case of UV irradiation, its gradual decomposition was observed, while electron beam exposure resulted in the deposition of amorphous carbon on its surface.
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Application of correlative AFM/SEM microscopy
Hegrová, Veronika ; Fejfar, Antonín (referee) ; Konečný, Martin (advisor)
This thesis is dealing with application of Correlative Probe and Electron Microscopy. All measurements were carried out by atomic force microscope LiteScope which is designed especially to be combined with electron microscopes. Advantages of Correlative AFM/SEM Microscopy are demonstrated on selected samples from field of nanotechnology and material science. Application of the correlative imaging was proposed and then realized particularly in case of low-dimensional structures and thin films. Further, this thesis deals with the possibility of combining Correlative AFM/SEM Microscopy with other integrated techniques of an electron microscope such as Focused Ion Beam and Energy Dispersive X-rays Spectroscopy.
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Fabrication and application of graphene-metal heterostructure in biosensing by Surface Enhenced Raman Spectroscopy
Hegrová, Veronika ; Édes, Zoltán (referee) ; Konečný, Martin (advisor)
This thesis deals with fabrication of graphene/metal heterostructures and their application in biosensing by surface-enhanced Raman spectroscopy. The heterostructures are fabricated by selective deposition of gold colloidal nanoparticles onto silicon substrate, where the termination of both the gold colloidal solution and the silicon surface is controlled. Further, the assembled gold colloids are overlaid by graphene monolayer. The experiments have proved, that it is possible to observe the presence of biomolecules at very low concentrations if the parameters of graphene/metal heterostructures are well selected. The combination of both graphene and metal SERS properties have demonstrated their appropriateness for utilization in bisensing.
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Advanced SPM techniques for measuring electrical properties of materials
Kramář, Jan ; Konečný, Martin (referee) ; Pavera, Michal (advisor)
This bachelor thesis is concerned about development of local electric properties characterization technique of sample in contact mode of Atomic Force Microscopy. The research part describes the most expanded techniques of characterization of local electric properties using Scanning Probe Microscopy. For realization was chosen Scanning Spreading Resistance Microscopy. Important part of this technique is current amplifier. For that reason, operational amplifiers, circuits with them and implementation of new amplifier on microscop are described. Last chapter is dedicated to description of samples, which were used to test functionality of the amplifier and technique.
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