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DFT calculations of graphene regarding to biosenzoric applications
Špaček, Ondřej ; Friák, Martin (referee) ; Bartošík, Miroslav (advisor)
This diploma thesis is focused on calculation of both structure and electronic properties of the graphene after the adsorption of atomic and molecular oxygen and urea using the Density Functional Theory (DFT). The influence of van der Waals interactions on the structure and adsorption energy is studied, as well as influence of the thermal corrections, the charge density spatial distribution and the electronic doping of graphene after the adsorption of the adsorbant on the graphene.
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DFT calculations of graphene regarding to biosenzoric applications
Špaček, Ondřej ; Friák, Martin (referee) ; Bartošík, Miroslav (advisor)
This diploma thesis is focused on calculation of both structure and electronic properties of the graphene after the adsorption of atomic and molecular oxygen and urea using the Density Functional Theory (DFT). The influence of van der Waals interactions on the structure and adsorption energy is studied, as well as influence of the thermal corrections, the charge density spatial distribution and the electronic doping of graphene after the adsorption of the adsorbant on the graphene.
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Correlated microscopy of electronic and material properties of graphene grown on diamond thin films
Rezek, Bohuslav ; Čermák, Jan ; Varga, Marián ; Tulic, S. ; Skákalová, V. ; Waitz, T. ; Kromka, Alexander
In this work we compare growth of graphene on diamond thin films that enable large area processing. We use films with different crystal size and surface roughness to obtain deeper insight into formation and properties of GoD. The diamond films are coated by a nm thin sputtered Ni layer and heated to 900°C in a forming gas atmosphere (H2/Ar) to initiate catalytic thermal CVD process. The samples are cleaned from residual Ni after the growth process. We employ scanning electron microscopy, Raman micro-spectroscopy and Kelvin probe force microscopy to correlate material, structural, and electronic properties of graphene on diamond. We show how grain size and grain boundaries influence graphene growth and material and electronic properties. For instance we show that the grain boundaries (with non-diamond carbon phases) in diamond films have an important role. They influence the electronic properties and they are beneficial for forming graphene on diamond higher quality.
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Microscopic characterization of graphene material and electronic quality across neighbouring, differently oriented copper grains
Čermák, Jan ; Yamada, T. ; Ganzerová, Kristína ; Rezek, Bohuslav
We study graphene grown across the boundary of three such grains having bright, medium, and dark color in reflection. Raman micro-spectroscopy proves presence of mostly a monoor bi-layer graphene on all the grains. Yet intensity of Raman 2D band is grain-dependent: highest at the darkest grain and lowest at the brightest one. Contrary, conductive atomic force microscopy detects the highest conductivity at the brightest grain and the lowest current at the darkest grain. This is attributed to dominant electrical current path through graphene and underlying oxide thickness of which also depends on the type of copper grain. We correlate and discuss the results with view to better understanding of graphene growth and electronic properties on large area copper substrates.
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