Charge Transport in Graphene-based multi-molecules junctions

The realization of stable and reliable molecular junctions taking advantage of graphene electrodes faces several issues. Nanoscale gaps with graphene electrodes can indeed exhibit signatures mimicking those of molecules, with gate-dependent resonance features [1,2]. Substrate effects can also play a role: Silicon dioxide has for instance been reported to yield feature-rich charge-transport characteristics in nanoscale graphene gaps, primarily due to switching within the oxide [3].
We report here on the realization of mechanically and electronically robust graphene-based multi-molecule junctions [4]. The mechanical stability is achieved by anchoring molecules directly to the substrate using silanization, rather than to graphene electrodes. The electronic stability is due to a large overlap between the electronic π-systems of neighboring head groups. The nature of the stacking leads to junctions less sensitive to the electrode properties. The junctions are reproducible throughout several devices and operate up to room temperature.

[1] M. El Abbassi et al. Nanoscale 9, 17312 (2017)
[2] V.M. García-Suarez,et al., Nanoscale 10, 18169 (2018)
[3] L. Posa et al., Nano letters 17, 6783 (2017)
[4] M. El Abbassi et al., to be submitted