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Modification of semiconductor nanowire growth
Pejchal, Tomáš ; Grym, Jan (referee) ; Kolíbal, Miroslav (advisor)
This diploma thesis deals with the growth of semiconductor nanowires on Ge(111) surface. The nanowires were prepared by means of PVD (physical vapor deposition). The growth was calatyzed by Au colloidal nanoparticles. An impact of different growth conditions on nanowire morfology is presented. It is demonstrated that Ge nanowires grow preferentially along axis. Ge wires with orientation were observed as well.
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Preparation of graphene layers by MBE
Čalkovský, Martin ; Bábor, Petr (referee) ; Mach, Jindřich (advisor)
This bachelor's thesis deals with growth of graphene by molecular beam epitaxy (MBE). The theoretical section explains the preperation, properties, and detection methods of the material graphene, and the MBE method of graphene preparation is discussed in detail. In the experimental section, optimization of the sublimation carbon source and its properties are shown. Further experiments dealing with the preparation of graphene on Cu and Ge substrates are also described. The presence of graphene structures is proven by Raman spectroscopy.
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Passivation of germanium surface using ALD
Kuba, Jakub ; Polčák, Josef (referee) ; Kolíbal, Miroslav (advisor)
The thesis deals with passivation of germanium surfaces by chemical etching and atomic layer deposition (ALD). Attention was paid to the rate of oxidation of germanium surfaces after selected passivation methods and the composition of the germanium suboxides. In the thesis selected methods for germanium oxide removal are reviewed and a brief description of the methods used for analysis (XPS) and thin film deposition (ALD) is given.
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Preparation of Cu3(Si0.5Ge0.5) Nanoplatelets
Dřínek, Vladislav ; Fajgar, Radek ; Palatinus, Lukáš ; Klementová, Mariana ; Novotný, F.
The nanoplatelets possess composition corresponding to Cu3(Si0.5Ge0.5). The 3D collection of electron diffraction patterns has shown that the rooom-temperature structure of the nanoplatelets corresponds to the ?-Cu3Si phase. Evaluation of the diffraction pattern shows that the structure has trigonal symmetry with long period incommensurate modulation. it can be approximately described in a 36-fold superstructure with trigonal unit cell and cell dimensions a=b=16.1A6, c=21.8A6.
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Difúze 71Ge a 68Ge v Mg a ve slitině Mg-2Al
Čermák, Jiří ; Eversheim, D. ; Rothová, Věra ; Stloukal, Ivo
Measurement of Ge diffusion coefficients in Mg and in Mg-1.8 wt.% Al alloy is presented in this work. Two techniques of Ge deposition and two annealing atmospheres (Ar and Ar + Cl2) were tested which might reveal possible influence of hold-up effect at the free surface on the diffusion behavior. The present results are compared with the literature data for volume diffusion of other impurities in Mg.
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