Effects of Ti additives on structural and electric properties of Cr- and Ti-codoped ZnO layers

Abstract

We investigate the effects of Ti-codoping on the structural and electrical properties of the ZnCrTiO layers grown on the Pt (111)/Ti/Al2O3 (0001) substrates by co-sputtering of ZnCrO and Ti. The ZnCrTiO layers with the Ti contents of 0.2-0.3 at.% reveal the enhanced disorder-activated Raman modes, attributing to increased lattice-displacement-induced phonon scattering due to the incorporation of Ti additives. In comparison with ZnCrO, the ZnCrTiO layers exhibit the improved ferroelectric properties with one order of magnitude-increased remnant polarization. This causes a polarization-dependent asymmetric hysteresis behavior in the Pt/ZnCrTiO/Pt top-to-bottom metal-ferroelectric-metal device, suggesting potential applications for two-terminal ferroelectric-tunneling resistive memories. (C) 2013 AIP Publishing LLC.