Spelling suggestions: "subject:"initio"" "subject:"abinitio""
91 |
Molecular Electronics : Insight from Ab-Initio Transport SimulationsPrasongkit, Jariyanee January 2011 (has links)
This thesis presents the theoretical studies of electronic transport in molecular electronic devices. Such devices have been proposed and investigated as a promising new approach that complements conventional silicon-based electronics. To design and fabricate future nanoelectronic devices, it is essential to understand the conduction mechanism at a molecular or atomic level. Our approach is based on the non-equilibrium Green's function method (NEGF) combined with density functional theory (DFT). We apply the method to study the electronic transport properties of two-probe systems consisting of molecules or atomic wires sandwiched between leads. A few molecular electronic devices are characterized; namely, conducting molecular wires, molecular switches and molecular recognition sensors. The considered applications are interconnection of different nanoelectronic units with cumulene molecular wires; adding switching functionality to the molecular connectors by applying stress to the CNT-cumulene-CNT junction or by introducing phthalocyanine unit; sensing of individual nucleotides, e.g., for DNA sequencing applications. The obtained results provide useful insights into the electron transport properties of molecules. Several interesting and significant features are analyzed and explained in particular such as, level pinning, negative differential resistance, interfering of conducting channels etc.
|
92 |
New quaternary amorphous materials Si-B-C-N: reactive magnetron sputtering and an ab-initio studyHouska, Jiri January 2007 (has links)
Doctor of Philosophy / First part of the thesis is focused on experimental preparation of new hard quaternary amorphous materials Si-B-C-N with high thermal stability. Materials were prepared in the form of thin films using reactive magnetron sputtering. The technique used proved to be suitable for reproducible synthesis of these materials. The Si-B-C-N films were generally found to be amorphous with low compressive stress and good adhesion to silicon or glass substrates. The process and film characteristics were controlled by varying the sputter target composition, the Ar fraction in the N2–Ar gas mixture, the negative rf-induced substrate bias, and the substrate temperature. Main conclusions describe the relationships between process parameters, discharge and deposition characteristics and film properties (elemental composition, chemical bonding structure, material hardness, compressive stress or electrical conductivity of materials prepared). Second part of the thesis is focused on ab-initio simulations of structures of experimentally prepared Si-B-C-N materials. In the performed liquid-quench simulations, the Kohn-Sham equations for the valence electrons are expanded in a basis of plane wave functions, while core electrons were represented using Goedecker-type pseudopotentials. We simplified the ion bombardment process by assuming that the primary impact creates a localized molten region of high temperature and sufficiently short cooling time, commonly referred to as a thermal spike. Main conclusions deal with N2 formation in studied materials, effect of implanted Ar on structure and properties of prepared materials, ability of Si to relieve that part of compressive stress which is caused by implanted Ar, and ability of B to improve thermal stability of Si-B-C-N materials. The calculated results are compared with experiment.
|
93 |
Thermochemistry and kinetics for the oxidative degradation of dibenzofuran and precursorsSebbar, Nadia. January 1900 (has links)
University, Diss., 2006--Karlsruhe.
|
94 |
First principles calculations of LaMnO 3 surface reactivityMastrikov, Yuri, January 2008 (has links)
Stuttgart, Univ., Diss., 2008.
|
95 |
Inter and intramolecular interactions between divalent selenium centersLari, Alberth. January 2008 (has links)
Heidelberg, Univ., Diss., 2008. / Online publiziert: 2008.
|
96 |
Multipolnäherungen für lokale KorrelationsverfahrenHetzer, Georg. January 2000 (has links)
Stuttgart, Univ., Diss., 2000.
|
97 |
Experimentelle und quantenchemische Untersuchungen an Verbindungen aus der Umsetzung von 2,2-Dimethylpropylidinphosphan mit Organoelementhalogeniden der 13. und 16. GruppeLöw, Ralph. January 2000 (has links)
Stuttgart, Univ., Diss., 2000.
|
98 |
Development of a new ab initio method for NMR chemical shifts in periodic systemsSebastiani, Daniel. January 2001 (has links)
Stuttgart, Univ., Diss., 2001.
|
99 |
FTIR-Messungen und quantenchemische Rechnungen an Sondenmolekülen auf lewis- und brønstedsauren Y-ZeolithenHübner, Georg Albrecht. January 2002 (has links)
Stuttgart, Univ., Diss., 2002.
|
100 |
Ab-initio statistical mechanics for ordering and segregation at the (110) surface of Ni90%-AlDrautz, Ralf. January 2003 (has links) (PDF)
Stuttgart, Univ., Diss., 2003.
|
Page generated in 6.496 seconds