Large memory window and tenacious data retention in (0001) ZnO:Cr ferroelectric memristive device prepared on (111) Pt layer

The high-performance ferroelectric memristive device was realized by fabricating a top-to-bottom metal-insulator-metal structure of Pt/ZnO:Cr/Pt by using a high-quality ferroelectric (000l) ZnO:Cr layer, which had been directly grown on the Pt layer having a preferential orientation normal to the (111) plane. The ZnO:Cr layer clearly showed a ferroelectric signature with high Curie temperature of ∼375 K. The ferroelectric memristive-device of Pt/ZnO:Cr/Pt revealed an asymmetric hysteresis behavior in positive- and negative-voltage regions when the higher electric-field was applied to the device. This could be attributed to the difference in polarization-dependent Schottky emission rates, arising from the ionic motion of oxygen vacancies. The device exhibited a large memory window (∼12.2 V), a high on/off ratio (>103), and a tenacious data retention. These suggest the present type of the device scheme to hold great promise for applications in next-generation ferroelectric memristive-switching devices.