CNT-molecule-CNT (1D-0D-1D) van der Waals integration ferroelectric memory with 1-nm(2) junction area

Abstract

© 2022 Springer Nature Limited. The device's integration of molecular electronics is limited regarding the large-scale fabrication of gap electrodes on a molecular scale. The van der Waals integration (vdWI) of a vertically aligned molecular layer (0D) with 2D or 3D electrodes indicates the possibility of device's integration; however, the active junction area of 0D-2D and 0D-3D vdWIs remains at a microscale size. Here, we introduce the robust fabrication of a vertical 1D-0D-1D vdWI device with the ultra-small junction area of 1 nm(2) achieved by cross-stacking top carbon nanotubes (CNTs) on molecularly assembled bottom CNTs. 1D-0D-1D vdWI memories are demonstrated through ferroelectric switching of azobenzene molecules owing to the cis-trans transformation combined with the permanent dipole moment of the end-tail -CF3 group. In this work, our 1D-0D-1D vdWI memory exhibits a retention performance above 2000 s, over 300 cycles with an on/off ratio of approximately 10(5) and record current density (3.4 x 10(8) A/cm(2)), which is 100 times higher than previous study through the smallest junction area achieved in a vdWI. The simple stacking of aligned CNTs (4 x 4) allows integration of memory arrays (16 junctions) with high device operational yield (100%), offering integration guidelines for future molecular electronics. The van der Waals integration of molecular layer (0D) with 2D or 3D electrodes is limited at microscale junction. Here, the authors introduce 1D-0D-1D vdWI memory with 1 nm(2) junction achieved by cross-stacking t-CNT on molecularly assembled b-CNT.