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Vertical Graphene Tunneling Heterostructure with Ultrathin Ferroelectric BaTiO 3 Film as a Tunnel Barrier
Author(s) -
Chan HungLit,
Yuan Shuoguo,
Hao Jianhua
Publication year - 2018
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201800205
Subject(s) - materials science , heterojunction , quantum tunnelling , ferroelectricity , graphene , optoelectronics , doping , semiconductor , electrode , tunnel junction , nanotechnology , nanoscopic scale , dielectric , chemistry
Ferroelectric tunnel junctions (FTJs) have attracted enormous interests as one of the promising candidates for next‐generation non‐volatile resistance memories. In this work, we report a novel FTJ employing both two‐dimensional material and semiconductor electrode, in the graphene/BaTiO 3 /Nb:SrTiO 3 heterostructure, yielding an interesting tunneling electroresistance (TER) effect. We investigate the TER dependence on Nb doping concentrations from 0.1 to 1.0 wt% in the semiconductor electrode. In addition to modulating barrier height by ferroelectric polarization reversal, the ON/OFF resistance ratio can be tuned by adjusting Nb doping concentrations due to further modulation of barrier width. An optimized ON/OFF ratio above 10 3 of the device is observed when introducing 0.1 wt% Nb concentration at room temperature. Furthermore, good retention property and switching reproducibility can be achieved in the devices. The results provide a novel pathway to design the graphene‐based FTJ at the nanoscale, which is useful for developing non‐volatile memory devices with enhanced performance.