Propriedades de transporte elétrico em baixas temperaturas em heteroestruturas Zn1-xCdxO/CdO crescidas pela técnica Spray Pirólise

In this thesis we study how the electrical transport properties in Zn1-xCdxO/CdO, heterostructures grown by spray pyrolysis, modified by doping and growing on substrates of glass and silicon. In the glass substrate, the x-doping values in the heterostructures were 0.50; 0.60; 0.75 and 0.95 and in silicon 0.60 and 0.95. CdO and Zn0,40Cd0,60O films were also grown on glass and silicon to analyze the contribution of these layers to heterostructures. From the diffractograms obtained from all the samples, it was verified that all are polycrystalline with phase-centered cubic structure (CFC) and that in the heterostructures grown on glass, the crystallite size is larger with the increase of doping. From the scanning electron microscopy (SEM) images of the surface of the samples, it was found that those grown on a glass substrate are less rough and those grown on silicon have domes on the surface. From the measurements of Hall effects it was observed that the samples are n-type independent of the substrate, having a high concentration of carriers being higher in the samples grown in glass, while the mobility was higher in the samples grown in silicon varying in up to four orders of magnitude. guarantee compared to those grown in glass. The high mobility in the samples grown on silicon was attributed to the domes. Electrical characterization and magnetotransport measurements were performed at temperatures ranging from 1.9 to 300 K and magnetic fields up to 9 T. All samples grown on glass showed metal-insulator transition (TMI) with different transition temperatures. The TMI observed in samples grown on glass is due to the degree of disorder being known as an Anderson-type transition. The heterostructure grown on silicon Zn0.40Cd0.60O/CdO also presented the TMI, but of the Mott type, which was verified by measuring resistance as a function of temperature (RT) applying a magnetic field. The Zn0.05Cd0.95O/CdO heterostructure and the CdO film grown on silicon showed insulating behavior in the RT curves throughout the ...