Polarity Control of the Schottky Barrier in Wurtzite Ferroelectrics

Memory devices with a high speed and low energy are highly desired for next-generation nanoelectronics. Here, using the switchable polarization in magnesium-substituted zinc oxide, a simple metal oxide with a polar wurtzite structure, the tunability of the Schottky barrier formed at the ferroelectric-metal interfaces is demonstrated. Through comprehensive analyses involving microstructural study and scanning probe microscopy, our work establishes the effect of magnesium doping, leading to the emergence of ferroelectricity and switchable polarization, in solution-processed zinc oxide films on glass substrates, demonstrated through both spectroscopic probing of piezoresponse and global poling techniques. Concomitantly, with magnesium doping, the electromechanical performance of the films is enhanced by ∼180%. Furthermore, doped films exhibit bias-dependent asymmetric resistive switching behavior attributed to the polarity-modulated back-to-back Schottky diode configuration leading to off/on resistance ratios of approximately 100. Our research findings unveil switchable polarization and a polarity-controlled Schottky barrier, and thus, modulation of electronic transport in solution-processed simple metal oxide films with a hexagonal wurtzite crystal structure thereby raises the translation prospects of ferroelectric electronic devices for information storage and memristive applications.