Growth and characterization of epitaxial oxide-based electron and hole-doped thin films and their heterostructures

Abstract

The main goal of this dissertation is the study of the effects induced by quantum confinement in transition-metal oxides quantum wells (QWs). The field of possible applications of oxide-based heterostructures (oxide-based nanoelectronics, spintronics, quantum computation, excitonic devices, energy conversion in solar cells, etc.) is very ample and growing, thanks to the many fascinating and exotic properties of transition-metal oxides and their versatility as well. p-type SrMnO3/La0.7Sr0.3MnO3/SrMnO3 QWs and n-type SrCuO2/Sr0.9La0.1CuO2/SrCuO2 QWs have been studied. The first part of my work has been devoted to the investigation of quantum confinement achievement using a Mott insulator with a small band gap. The observed results suggest that this type of material can be successfully used in QWs. As a final result of my work, the achievement of dimensional effects induced by the layering on the normal state of both investigated systems (n and p-doped) has been assessed. In addition, the layering has been shown to influence the superconducting state of the investigated n-doped QWs and on the metal-to-insulator transition of the p-doped QWs. The investigation of the behavior of each layer constituent the QW (both n and p-doped) is relevant in view of future growth of proximate p-n doped systems. Part of my work, therefore, has been devoted to the study of the properties of (Sr,La)CuO2 thin films. The study of electrical transport properties of SLCO thin films as a function of the doping has allowed to relate the presence of the low temperature upturn in the (Sr,La)CuO2 resistivity versus temperature curves the quantum interference effects produced by weak localization effects. Furthermore, the presence of low temperature Fermi liquid behaviors in SLCO thin films has also been observed... [edited by Author]