Tunable Ferroelectric Properties in Highly (0002)-Textured Zn_1-xMg_xO Films

This work systematically investigates the profound influence of Mg content (x = 0.20-0.54) on the structural evolution, ferroelectric properties, and defect states of Zn_1-xMg_xO thin films. The [111]-oriented Pt layer serves as an effective growth template, promoting highly [0002]-preferred orientation growth of the wurtzite-structured films while significantly elevating the Mg concentration threshold for phase separation. According to our coupled experimental and computational results, both remanent polarization and coercive field exhibit pronounced intrinsic compositional dependence. Photoluminescence spectroscopy reveals that Mg content substantially modulates defect types and concentrations, with the densities of both $V_O^{+}$ and $V_O^{2+}$ defects increasing sharply at high Mg concentration. We establish that defect engineering governs the observed switching current peak-splitting phenomenon. This study not only maps the intricate relationship between Mg doping, crystal structure, ferroelectric properties, and defect configuration in Zn_1-xMg_xO, but also demonstrates its superior potential for applications in next-generation memory devices requiring tunable polarization and robust endurance.