Tunneling electroresistance of MgZnO-based tunnel junctions.

We investigated the tunneling electroresistance (TER) in metal/wurtzite-MgZnO/metal junctions for applications in nonvolatile random-access memories. A resistive switching was detected utilizing an electric-field cooling at ±1V and exhibited a TER ratio of 360%-490% at 2K. The extracted change in the average barrier height between the two resistance states gave an estimation of the MgZnO electric polarization at 2.5μC/cm2 for the low-temperature limit. In addition, the temperature-dependent TER ratio and the shift of the localized states energies at the barrier interface supported the ferroelectric behavior of the MgZnO tunnel-barrier. From the first-principles calculations, we found a similar effect of the barrier height change coming from the reversal of ZnO electric polarization. The possibility of using metal electrodes and lower growth temperatures, in addition to the ferroelectric property, make the ZnO-based memory devices suitable for CMOS integration. [ABSTRACT FROM AUTHOR]