2, PTB, Braunschweig, , Germany
Carbon nanomembranes (CNMs) are two-dimensional materials that are made by cross-linking self-assembled monolayers (SAMs) of aromatic molecules via low energy electron irradiation. Previous studies of the charge transport in molecular junction incorporating SAMs and CNMs of oligophenyl thiols has been carried out by using conical eutectic Gallium-Indium (EGaIn) top-electrodes1 and conductive probe atomic force microscopy (CP-AFM)2. Additional investigations of the dielectric properties of pristine SAMs and CNMs were performed by impedance spectroscopy on EGaIn tunneling junction. Here we demonstrate the fabrication and characterization of all-carbon capacitors (ACCs) composed of multilayer stacks of CNMs that are sandwiched between two graphene sheets that act as conducting electrodes. Three-layer and six-layer CNMs were used as dielectric layers between the top and bottom graphene electrodes. The junction area of the nanocapacitors ranges from 1 to 2500 µm2. Whereas the use of CVD graphene grown on copper only led to small-area capacitors with low yield, the utilization of nanocrystalline (NC) graphene from annealed CNMs and the involved avoidance of copper residuals between the electrodes caused high yield of large-area capacitors with a dielectric thickness of down to 4.5 nm. The results suggest that the combination of NC graphene and CNMs as well as other 2D materials in nanoscale functional devices may provide a promising approach toward further development of molecular electronics devices.
1 P. Penner, X. Zhang, E. Marschewski, F. Behler, P. Angelova, A. Beyer, J. Christoffers, A. Gölzhäuser, J Phys Chem C, 2014, 118, 21687.
2 X. Zhang, E. Marschewski, P. Penner, A. Beyer and A. Gölzhäuser, JOURNAL OF APPLIED PHYSICS, 2017, 122, 055103.