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STM/STS study of bimetallic nanostructures on silicon surfaces
Zimmermann, Petr ; Sobotík, Pavel (advisor) ; Mysliveček, Josef (referee)
In this study we examine linear nanostructures consisting of metals of III. (Al, In) and IV. (Sn) group on the Si(001)2×1 surface by means of scanning tunnelling microscopy & spectroscopy. Atoms on the surface align into atomic chains growing perpendicularly to the dimer rows of the surface reconstruction. The chain structure consists of dimers that adsorb in the troughs between the dimer rows of the surface reconstruction. We observe that the chains consist of sequences of homodimers of either elements combining with heterodimers. The InSn chain structure is analysed with regard to theoretical ab-initio calculations of the chain dimer structure. The model is then applied to the Al-Sn system. We observe that the Al-Sn chains tend to consist of aligned heterodimers. The appearance of heterodimers in STM depends on the chemical composition of the neighbouring dimers. We can also observe the tendency of chains to agglomerate and via Sn atoms create quasi periodic 2D structures. The electronic structure of an Al, Sn and mixed AlSn dimer is studied by means of tunnelling spectroscopy. Despite its small, nonzero density of states on the Fermi energy, the character of the mixed dimer appears to be rather non-conductive.
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Preparation of the Si(110)-Tl surface for deposition of organic molecules
Slezák, Peter ; Kocán, Pavel (advisor) ; Zimmermann, Petr (referee)
This bachelor thesis deals with the formation of an anisotropic surface Si (110) -Tl, which will serve as a substrate for the deposition of organic molecules of copper phthalocyanines. The aim was to identify relevant preparation parameters and optimize the producting process of surface Si (110) with the reconstruction (16x2), to find the best parameters for deposition of thallium on this surface so as to produce a surface Si (110) -Tl with reconstruction (1x1) and test the suitability of this surface as a substrate for further deposition of organic molecules. In the course of the work, the apparatus used for measurements is described, the individual measurement procedures and the physical principles associated with STM operation are also described.
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Interaction of organic molecules with metal passivated semiconductor surfaces studied via STM
Zimmermann, Petr ; Sobotík, Pavel (advisor)
Title Interaction of Organic Molecules with Metal Passivated Silicon Surfaces Studied via STM Author Petr Zimmermann Department Department of Plasma and Surface Science Supervisor Doc. RNDr. Pavel Sobotík, CSc. Department of Plasma and Surface Science Abstract Organic molecules offer a wide range of optical, electronic or chemical properties. Coupling them to silicon could pave way to novel applications and devices, however, a controlled molecular functionalization of silicon remains challenging due to the presence of highly reactive dangling bonds on its surfaces. We attempt to decrease the reactivity of low index silicon surfaces with an ultra-thin layer of a metal adsorbates and study their interaction with organic molecules via scanning tunnelling microscopy. In the first part we investigate the interaction of ethylene, a small unsaturated molecule, with tin and indium 1D chains grown on Si(001) - 2 × 1. The chains consist of dimers structurally analogous to the dimers of the underlying Si(001) - 2 × 1 surface. Aided by photoelectron spectroscopy we find that the Sn chains are less reactive than the Si(001) surface and that the absence of a π dimer bond renders indium chains inert. In the second part we study the interaction of copper phthalocyanine, a small macrocyclic heteroaromatic compound, with the...
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Interaction of organic molecules with metal passivated semiconductor surfaces studied via STM
Zimmermann, Petr ; Sobotík, Pavel (advisor)
Title Interaction of Organic Molecules with Metal Passivated Silicon Surfaces Studied via STM Author Petr Zimmermann Department Department of Plasma and Surface Science Supervisor Doc. RNDr. Pavel Sobotík, CSc. Department of Plasma and Surface Science Abstract Organic molecules offer a wide range of optical, electronic or chemical properties. Coupling them to silicon could pave way to novel applications and devices, however, a controlled molecular functionalization of silicon remains challenging due to the presence of highly reactive dangling bonds on its surfaces. We attempt to decrease the reactivity of low index silicon surfaces with an ultra-thin layer of a metal adsorbates and study their interaction with organic molecules via scanning tunnelling microscopy. In the first part we investigate the interaction of ethylene, a small unsaturated molecule, with tin and indium 1D chains grown on Si(001) - 2 × 1. The chains consist of dimers structurally analogous to the dimers of the underlying Si(001) - 2 × 1 surface. Aided by photoelectron spectroscopy we find that the Sn chains are less reactive than the Si(001) surface and that the absence of a π dimer bond renders indium chains inert. In the second part we study the interaction of copper phthalocyanine, a small macrocyclic heteroaromatic compound, with the...
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Interaction of organic molecules with metal passivated semiconductor surfaces studied via STM
Zimmermann, Petr ; Sobotík, Pavel (advisor) ; Plšek, Jan (referee) ; Šikola, Tomáš (referee)
Title Interaction of Organic Molecules with Metal Passivated Silicon Surfaces Studied via STM Author Petr Zimmermann Department Department of Plasma and Surface Science Supervisor Doc. RNDr. Pavel Sobotík, CSc. Department of Plasma and Surface Science Abstract Organic molecules offer a wide range of optical, electronic or chemical properties. Coupling them to silicon could pave way to novel applications and devices, however, a controlled molecular functionalization of silicon remains challenging due to the presence of highly reactive dangling bonds on its surfaces. We attempt to decrease the reactivity of low index silicon surfaces with an ultra-thin layer of a metal adsorbates and study their interaction with organic molecules via scanning tunnelling microscopy. In the first part we investigate the interaction of ethylene, a small unsaturated molecule, with tin and indium 1D chains grown on Si(001) - 2 × 1. The chains consist of dimers structurally analogous to the dimers of the underlying Si(001) - 2 × 1 surface. Aided by photoelectron spectroscopy we find that the Sn chains are less reactive than the Si(001) surface and that the absence of a π dimer bond renders indium chains inert. In the second part we study the interaction of copper phthalocyanine, a small macrocyclic heteroaromatic compound, with the...
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Preparation of the Si(110)-Tl surface for deposition of organic molecules
Slezák, Peter ; Kocán, Pavel (advisor) ; Zimmermann, Petr (referee)
This bachelor thesis deals with the formation of an anisotropic surface Si (110) -Tl, which will serve as a substrate for the deposition of organic molecules of copper phthalocyanines. The aim was to identify relevant preparation parameters and optimize the producting process of surface Si (110) with the reconstruction (16x2), to find the best parameters for deposition of thallium on this surface so as to produce a surface Si (110) -Tl with reconstruction (1x1) and test the suitability of this surface as a substrate for further deposition of organic molecules. In the course of the work, the apparatus used for measurements is described, the individual measurement procedures and the physical principles associated with STM operation are also described.
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STM/STS study of bimetallic nanostructures on silicon surfaces
Zimmermann, Petr ; Mysliveček, Josef (referee) ; Sobotík, Pavel (advisor)
In this study we examine linear nanostructures consisting of metals of III. (Al, In) and IV. (Sn) group on the Si(001)2×1 surface by means of scanning tunnelling microscopy & spectroscopy. Atoms on the surface align into atomic chains growing perpendicularly to the dimer rows of the surface reconstruction. The chain structure consists of dimers that adsorb in the troughs between the dimer rows of the surface reconstruction. We observe that the chains consist of sequences of homodimers of either elements combining with heterodimers. The InSn chain structure is analysed with regard to theoretical ab-initio calculations of the chain dimer structure. The model is then applied to the Al-Sn system. We observe that the Al-Sn chains tend to consist of aligned heterodimers. The appearance of heterodimers in STM depends on the chemical composition of the neighbouring dimers. We can also observe the tendency of chains to agglomerate and via Sn atoms create quasi periodic 2D structures. The electronic structure of an Al, Sn and mixed AlSn dimer is studied by means of tunnelling spectroscopy. Despite its small, nonzero density of states on the Fermi energy, the character of the mixed dimer appears to be rather non-conductive.
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Zhodnocení přírodních podmínek a kvality chovu mufloní zvěře na Melechově
Zimmermann, Petr
The thesis concentrates on assessment of mouflon population and it's habitat. The survey revealed that the mouflons had consumed 0,3% of herbaceous and grass biomass and 1,2% of timber biomass during the growing season. Outside the growing season the lack of natural feed was compensated by the good quality care taken by gamekeepers. The number of 30 animals in the population was estimated by combination of different measuring methods. The damage caused to young spruce trees proved to be the most dangerous influence that the mouflons have on woodlands. The quality of mouflon game was assessed by measuring the horns according to the CIC standards and by craniometric measuring of the heads and was found to be above-average. There are no health problems within the population. The local environment is very suitable for keeping mouflon game.
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