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In modern times the increasing complexity of transistors and their constant decreasingsize require more effective techniques to display and interpret the processes that are inside of devices. In this work, we are modeling a two‐dimensional n‐MOSFET with a long channeland uniformly doped substrate. We assume that this device is a large geometry device so that short‐channel and narrow‐width effects can be neglected. As a result of the thesis, a demonstration program was built. In this executable file, the user can choose parameters of the MOSFET‐model: drain and gate voltage, and different geometrical parameters of the device (junction depth and effective channel length). In the advanced regime of the program, the user can also specify the model re‐calculation parameter, doping concentration in n+ and bulk regions. The program shows the channel between the source and drain region with surface diagrams of carrier density and potential energy as an output. It is possible to save all calculated results to a file and process it in any other program, for example, plot graphics in Matlab or Matematica. The model can be used in lectures that are related to semiconductor physics in order to explain the basic working mechanisms of MOSFETs as well as for further detailed analysis of the processes in MOSFETs. It is possible to use our modeling techniques to rebuild the model in another computer language, or even to build other models of transistors, performing similar calculations and approximations. It is possible to download the executable file of the model here: http://studentdevelop.com/projects/MOSFET_model.zip

The structure, potential energy functions and vibrational spectra of several cyclic and bicyclic molecules have been investigated using several spectroscopic techniques and high-level ab initio and density functional theory (DFT) calculations. Laser induced fluorescence and Raman spectroscopies were used to study the conformation of 2- indanol in the electronic ground and excited states. These, along with detailed ab initio calculations, confirmed the existence of four different stable conformations with the one undergoing an intermolecular hydrogen bonding being the most stable. A theoretical two-dimensional surface in terms of the ring-puckering and the hydroxyl group internal rotation vibrations was constructed. This work was extended to obtain preliminary insights on the conformations and ring-puckering frequencies of 3-cyclopenten-1-ol using ab initio and DFT calculations. Infrared and Raman spectra were also utilized to study the structures and vibrational spectra of -crotonolactone and 2,3-cyclopentenopyridine (pyrindan). Ab initio results showed that -crotonolactone is rigidly planar in the electronic ground state and has a nearly harmonic ring-puckering potential function. The calculated vibrational levels were shown to be in very good agreement with the experimental ring-puckering frequency from vapor-phase Raman observations. The structures, vibrational spectra, and potential energy functions of several cyclic molecules were reinvestigated using high-level ab initio computations, and detailed vibrational analyses based on DFT-B3LYP calculated frequencies were also carried out. A number of new insights were presented by re-evaluating the available experimental data for several cyclopentenes, silacyclobutanes and silacyclopentenes. It was found that the vibrational spectra of some deuterated cyclopentenes possess extensive coupling between several ring modes and other low-frequency modes. Reassignments of these spectra have been proposed. Frequencies from DFT-B3LYP calculations showed very good agreement with the experimental values for silacyclobutane and its derivatives. The presence of silicon and halogen atoms did not affect the accuracy of the DFT calculations. In addition, the ring-puckering potential energy function for silacyclopent-2-ene was studied and alternative assignments of the far-infrared results were proposed. The new assignments are in good agreement with computational results. Silacyclopent-2-ene and its -1,1-d2 isotopomer were shown to be slightly puckered with barriers of less than 50 cm-1.

In this research the so-called potential morphing method was used to generate reliable interaction potential energy surfaces for weakly bound complexes. The potential morphing method is based on the optimization of modified computed ab initio potential energy surfaces to give predicted spectroscopic data, in agreement with the experimental values. In the standard potential morphing procedure the computed ab initio potential is adjusted by scaling, shifting, and dilating transformations to reproduce the experimental data. In this research, selected systems have been chosen to be studied based on the availability of varied and accurate sets of experimental data. In the present work, accurate interaction potential energy surfaces are obtained for the weakly bound complexes: Ne:HCl, OC:HX (X = F, Cl, Br, I) and HI:CO2. A comprehensive study on the interaction potential of these systems provides fundamental perspectives on the influence of different intermolecular forces. In addition the ground state isotopic isomerization observed in the OC:HI system may suggest a possible structural change of proteins, and other biological macromolecules, in deuterated solvents. In this dissertation, an alternative approach to morphing the potential energy surfaces of non-covalent interactions is also presented. In this approach the morphed potential is generated as a linear combination of ab initio potentials, that are computed at different levels of theory. This new morphing approach is applied to OC:HCl and is found to be of similar accuracy to that of the previous morphing method. In addition, this new method is also extended from four-dimensions to six-dimensions and is applied to the OC:HF system to obtain a vibrationally-complete six-dimensional morphed potential.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 115-124).

Intermolecular potential energy functions for CO2 have been developed from first principles for use in heterogeneous systems, including one with explicit polarization. The intermolecular potentials have been expressed in a transferable form and parameterized from nearly exact electronic structure calculations. Models with and without explicit many-body polarization effects, known to be important in simulation of interfacial processes, are constructed. The models have been validated on pressure-density isotherms of bulk CO2 and adsorption in three metal-organic framework (MOF) materials. The present models appear to offer advantages over high quality fluid/liquid state potentials in describing CO2 interactions in interfacial environments where sorbates adopt orientations not commonly explored in bulk fluids. Thus, the nonpolar CO2-PHAST and polarizable CO2-PHAST* potentials are recommended for materials/interfacial simulations.

Not available / text

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [193]-203).

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--University of Oregon, 2005. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 79-80). Also available for download via the World Wide Web; free to University of Oregon users.