Electrical, Optical, and Thermal Properties of Nanostructures

This work presents the findings on the electrical, optical, and thermal properties of nanostructures and how they can be both characterized and used in various applications across nanotechnology from remote intracellular manipulation and biological diagnostics to spontaneous polarization and quantum devices. These findings include solutions to non-Fourier heat transport problems in both inorganics and organics, Raman and PL spectroscopy for the characterization of NCSiNWs, interactions between manmade nanostructures and biologicals, spontaneous polarization models in multiple dimensions which do not assume periodic boundary conditions which lead to the realization that nanostructures can have much greater spontaneous polarization than their bulk counterparts, plasmonic based diagnostics for human colon cancer, and the effects of quantum confinement on phonons and biexciton decoherence in QDs based quantum devices. With the two major investigations being the modelling of laser interactions with nanocrystalline silicon nanowires within cells and the creation of simplistic spontaneous polarization models and how the spontaneous polarization of a lattice can change greatly at nanoscale. In the first major investigation it is investigated as to why when a laser is shined on human and rat cells which contain nanocrystalline silicon nanowires, which were internalized through phagocytosis, one can see a wide range of effects from neuronal excitement to intracellular calcium increases and manipulation of cytoskeletal structures. In which possible causes that were investigated include electromagnetic, photoacoustic, and photothermal interactions between the laser, manmade nanostructures, and cells. To further model these interactions novel solutions to non-Fourier heat transport equations were created with various boundary conditions, including imperfect thermal contacts. After which it was deemed that the photothermal effect was the most likely cause of the cellular manipulations seen experimentally. In the second major investigation the effects of nanoscale on wurtzite lattices were investigated with regards to their spontaneous polarization. In this investigation it was discovered how one can accurately model spontaneous polarization through easy-to-use methods which one can perform with a pencil and paper, rather than the highly complex ab-initio Density Functional Theory based methods which require great computational power and knowledge on ab-initio based methods. From this it was discovered that the spontaneous polarization of nanostructures, such as quantum wells and quantum dots, can be multiple times greater than that of their bulk counterparts.