Efeitos da interface e da dopagem nas propriedades estruturais, óticas e elétricas de filmes finos de ZnO

Abstract

In this work, we described the structural, morphological, optical and electrical properties of the ZnO thin films undoped and chromium (Cr), copper (Cu), aluminium (Al) doped deposited using magnetron sputtering and co-sputtering method on glasses, Cr and niobium (Nb) substrates. For characterization of the samples were used the X-ray diffraction (XRD), X-ray reflectometry (XRR), UV-Vis spectroscopy in the visible region techniques and IxV plots. This work was divided in two parts, in the study I, ZnO films were grown on glasses substrates and the influence of the substrate temperature, RF power and films thickness at the structural, morphological and optical properties was studied. The results showed that all films grown exhibit characteristic peaks of hexagonal wurtzite phase with axis-c preferential orientation, the films roughness was very influenced by thickness and temperature and the gap energy varied with the films thickness. In the study II, thin films undoped and doped were grown at 300ºC on different substrates and the influence of kind of substrate, dopants, dopant concentration on the structural, morphological, optical and electrical properties was studied. Generally, all samples deposited on Cr substrates exhibit resistance lower than the samples deposited on Nb substrates. For some samples, an unusual behavior was observed at the moment of electrical measurements, after any voltage, different for each sample, the current fell abruptly.