Giant tunnelling electroresistance in metal/ferroelectric/semiconductor tunnel junctions by engineering the Schottky barrier.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28513590.
- Also identified by DOI 10.1038/ncomms15217 and PMC identifier 5442322.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Recently, ferroelectric tunnel junctions have attracted much attention due to their potential applications in non-destructive readout non-volatile memories. Using a semiconductor electrode has been proven effective to enhance the tunnelling electroresistance in ferroelectric tunnel junctions. Here we report a systematic investigation on electroresistance of Pt/BaTiO<sub>3</sub>/Nb:SrTiO<sub>3</sub> metal/ferroelectric/semiconductor tunnel junctions by engineering the Schottky barrier on Nb:SrTiO<sub>3</sub> surface via varying BaTiO<sub>3</sub> thickness and Nb doping concentration. The optimum ON/OFF ratio as great as 6.0 × 10<sup>6</sup>, comparable to that of commercial Flash memories, is achieved in a device with 0.1 wt% Nb concentration and a 4-unit-cell-thick BaTiO<sub>3</sub> barrier. With this thinnest BaTiO<sub>3</sub> barrier, which shows a negligible resistance to the tunnelling current but is still ferroelectric, the device is reduced to a polarization-modulated metal/semiconductor Schottky junction that exhibits a more efficient control on the tunnelling resistance to produce the giant electroresistance observed. These results may facilitate the design of high performance non-volatile resistive memories.