Evaluating the Performance of ZnO Based Rare Earth Element Doped Thin Films

Abstract

In DMS materials, magnetic ions replace a very small portion of the host semiconductor cation. We selected the transparent ZnO, which has a bandgap of 3.3 eV at ambient temperature, as the semiconducting host. Studies on 3d transition metal-doped ZnO showed that the magnetic moments were quite tiny. We looked into ZnO thin films doped with rare earth (RE) metal ions in light of more recent Gd in GaN studies that showed large magnetic moments. The 3d electrons in transition metals are exterior and delocalized, resulting in strong direct exchange interactions and high Curie temperatures, but the orbital momentum is often zero, resulting in small total magnetic moments per atom. The 4f electrons are localised in RE metals, and exchange interactions are indirect, via 5d or 6s conduction electrons, but the elevated orbital momentum leads to high total magnetic moments per atom, such as 3.27µB for Nd. Nd has a Curie point of 19 K. The findings of our investigation into Nd-doped ZnO films are presented in this work. In order to learn more about the electrical characteristics of films, hall measurements are used. Here, we made and examined ZnO films doped with various Nd concentrations. On a-plane Al2O3 or SiO2 substrates, the films are grown. Hall investigations of electrical properties revealed the presence of a degenerate, highly conducting, film–substrate interface layer for the films grown on Al2O3; such an effect can be avoided, for example, by using SiO2 substrates. No anomalous Hall effect was seen in the magnetotransport experiments, but there was a strong negative magneto resistance ratio, which can be explained by the system's paramagnetic reaction to the applied magnetic field. We want to keep using surface-sensitive methods to examine the magnetic characteristics of ZnO:RE thin films.