Achieving Ohmic conduction behavior at high electric field via interface manipulation

• DOI: 10.1016/j.apsusc.2020.146093
• Publication Date: 2020-03-14T06:45:32Z
• Authors: X.Y. Zhang; R.X. Xu; X.Y. Gao; M. Li; X.N. Shi; Y.D. Ji; F.J. Qian; J.Y. Fan; H.Y. Wang; W.-W. Li; H. Yang
• Keywords: 0103 physical sciences; 02 engineering and technology; 0210 nano-technology; 01 natural sciences

Abstract Interface in complex oxide heterostructures provides a new platform for uncovering emergent physical phenomena and engineering novel functionalities. Compared to the control of lateral interface in bilayer or multilayer complex oxide films, the investigation on manipulating the vertical interface in vertically aligned nanocomposite films is rarely studied so far. Here, the vertical interface effect on the leakage behavior of vertically aligned nanocomposite BaTiO3:Sm2O3 films grown on (1 1 1) Nb-SrTiO3 (Nb-STO) substrates is reported. We found that the vertical interface without visible misfit dislocations is formed between BaTiO3 and Sm2O3. Consequently, the leakage mechanism is determined to be Ohmic conduction up to an electric field of 1000 kV/cm. Also, the leakage current is reduced to be around 3 × 10−7 A/cm2, which is almost two and three orders of magnitude lower than that of BaTiO3:Sm2O3/(0 0 1) Nb-STO and pure BaTiO3/(1 1 1) Nb-STO films, respectively. This work demonstrates the ability to realize Ohmic conductive mechanism at high electric field and further provides a new pathway to reduce leakage current and improve ferroelectric polarization of ferroelectric oxide films by manipulating the vertical interface, which opens the door to the design of advanced nanostructures with the emergent functionalities.