Polarization-Mediated Modulation of Electronic and Transport Properties of Hybrid MoS<sub>2</sub>-BaTiO<sub>3</sub>-SrRuO<sub>3</sub> Tunnel Junctions.

Li, Tao; Sharma, Pankaj; Lipatov, Alexey; Lee, Hyungwoo; Lee, Jung-Woo; Zhuravlev, Mikhail Y; Paudel, Tula R; Genenko, Yuri A et al. · Nano Lett · 2017

basic_science · Level V

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Abstract

Hybrid structures composed of ferroelectric thin films and functional two-dimensional (2D) materials may exhibit unique characteristics and reveal new phenomena due to the cross-interface coupling between their intrinsic properties. In this report, we demonstrate a symbiotic interplay between spontaneous polarization of the ultrathin BaTiO<sub>3</sub> ferroelectric film and conductivity of the adjacent molybdenum disulfide (MoS<sub>2</sub>) layer, a 2D narrow-bandgap semiconductor. Polarization-induced modulation of the electronic properties of MoS<sub>2</sub> results in a giant tunneling electroresistance effect in the hybrid MoS<sub>2</sub>-BaTiO<sub>3</sub>-SrRuO<sub>3</sub> ferroelectric tunnel junctions (FTJs) with an OFF-to-ON resistance ratio as high as 10<sup>4</sup>, a 50-fold increase in comparison with the same type of FTJs with metal electrodes. The effect stems from the reversible accumulation-depletion of the majority carriers in the MoS<sub>2</sub> electrode in response to ferroelectric switching, which alters the barrier at the MoS<sub>2</sub>-BaTiO<sub>3</sub> interface. Continuous tunability of resistive states realized via stable sequential domain structures in BaTiO<sub>3</sub> adds memristive functionality to the hybrid FTJs. The use of narrow band 2D semiconductors in conjunction with ferroelectric films provides a novel pathway for development of the electronic devices with enhanced performance.