Caracterización eléctrica de uniones moleculares usando grafeno obtenido mediante exfoliación electroquímica.

Abstract

The miniaturization of electronic devices is a process that has been going on for more than 50 years, but, at the same time it’s reaching its limit by manufacturing 10 nm size transistors. In this context, molecular electronics, which is basically the use of a single molecule or a molecule monolayer connected between two or three electrodes to form a new electronic device, is a viable option to continue with this miniaturization process. On the other hand, there is a current trend in electronics to use semi-metallic carbón based electrodes (fullerenes, graphite, and graphene), due to i) their novelty properties and ii) because they help to avoid the use of noble metals, and/or potentially toxic materials. Thus, in this work, graphene nanosheets are obtained by electrochemical exfoliation to be used as an electrode in the study of molecule-electrode junctions (ME). Two types of graphene nanosheets are used; the so-called polydisperse graphene, with a wide thickness distribution, obtained directly from electrochemical exfoliation; and less dispersed graphene, with a lower thickness distribution, obtained by applying the cascade centrifugation technique to the polydisperse graphene. To study the ME junctions, it was used the break junction using a tunneling microscope (STM-BJ) technique. Finally, the conductance values of the ME junctions were compared with those obtained using gold as an electrode. The results show that the electrical properties of the molecular bonds are similar when using the two types of graphene and gold as electrodes.