This thesis describes a study from both a theoreticaL and an experimental point of view. I deveLop a new ru•deL for electron transport through networks of interconnected narnzparticLes In the... Show moreThis thesis describes a study from both a theoreticaL and an experimental point of view. I deveLop a new ru•deL for electron transport through networks of interconnected narnzparticLes In the Coulomb blockade regime and compare this ru•del tc experimental data. The main conclusion from this study is that cotunneLing does not give any significant contribution tc electron transport. Instead, transport is governed by perccIatLng paths thrcugh the netwcrk. Here, disorder In the array (in the form of variation of the Coulomb chargLng energy of the nanzparticLes) is the domLnating factor. Morecver, usLng Low—energy electron potentiometry, I visualise the f Low cf electrcns through the network. We find here that the contact resistance is negligibLe, and Chat the electi•zn flow 13 not impeded by small irregularities such as small and grain boundaries . Show less
By combining low-energy electron microscopy (LEEM) with pulsed laser deposition (PLD), we have created a unique set-up to study the first stages of growth of complex metal oxides. We... Show more By combining low-energy electron microscopy (LEEM) with pulsed laser deposition (PLD), we have created a unique set-up to study the first stages of growth of complex metal oxides. We demonstrate this by investigating the growth of SrTiO3 (STO) and LaAlO3 (LAO) on STO in real-time. We follow growth by monitoring the intensity and the full-width-half-maximum (FWHM) of the specular diffracted beam at various energies. For layer-by-layer growth, we find the anticipated intensity peaks at the completion of each layer, and an oscillatory FWHM with the maximum at half-layer coverage. In the LAO on STO case, for optimal growth conditions and a LAO thickness above the critical thickness of 4 unit cells the interface between the band insulators shows conductivity. We obtain an electronic fingerprint of the growing material, by measuring the intensity of the specular beam as a function of energy at regular intervals during growth. Extending this fingerprint with the intensity dependence on the momentum parallel to the surface allows us to extract the band dispersion of unoccupied electron states of the sample surface. Significant differences in the unoccupied band structure develop between samples which are conducting and non-conducting. Show less
