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Home > Research > Molecular Scale Electronic Transport (TELEM)

Molecular Scale Electronic Transport (TELEM)




Novembre 2020: URGENT

M2 internship with secured PhD grant: link to the PhD/intership offer
For any further information, please contact: maria-luisa.della-rocca@u-paris.fr


Our research

The goal of our research is to explore the fundamental properties of charge and spin quantum transport at the molecular scale in new hybrid structures composed of semiconducting or metallic contacts and single molecules or organic thin films. The device’s architecture can vary from a planar geometry (Figure 1a: Field effect transistor based on carbon nanotubes) to a vertical geometry (Figure 1b: molecular tunnel junction, diode). They are fabricated in our clean room in collaboration with the ITODYS chemistry lab. We also explore new alternative technological approaches by using carbon nanotubes and/or graphene as "electrical contacts" on the molecules towards a full-carbon electronics.

intro intro
Figure 1a: Image obtained by a scanning electron microscope of field effect transistors based on carbon nanotubes (PhD thesis of Philippe Petit). Figure 1b: Scheme of an Au/antraquinone/Au vertical molecular junction. Image taken from our recent article about quantum interferences phenomena: V. Rabache et al., JACS 135 10218–10221 (2013).

For more details about our research, please check the following link Research projects.

Quantum molecular electronics

Molecular electronics is born from the paradigm that an entire device could be condensed in a single molecule by designing/choosing its chemical structure (thus its electronic structure). The huge diversity offered by chemistry allows to produce molecules "mimicking" most of the electronic devices from the classical ones to the quantum ones (figure 2) and at the scale of only few nanometers.
Moreover, the reduced size of molecules and their low production cost made molecular/organic electronics as a serious alternative to standard inorganic semiconductor based electronics. Carbon nanotubes-based field effect transistors and organic electroluminescent diodes (OLEDs) are very advanced examples.
Recently, we are interested in transport properties of molecular junction based on cross-conjugated molecules like anthraquinone in search for understanding quantum interference effects (figure 2). Thermoelectric effects of molecular junctions are also investigated.

interferometre
Figure 2: Quantum interferences effect obtained in an anthraquinone-based junction. Image taken from our recent article about quantum interferences phenomena: V. Rabache et al., JACS 135 10218–10221 (2013).

Some very recent review articles about molecular electronics can be downloaded here, here and here.

Molecular spin electronics

Organic materials are also potentially excellente candidates as medium for propagation andstorage of spin information. This is due to the weak spin-orbit interaction and weak hyperfines interactions present in those organic materials (explained by the presence of light elements like C, N, O, H...). This specifity is attracting for the realisation of the future spin logic devices in which propagation and information storage are crucial. Moreover, as evoked before, intriguing new functionnalities like, for instance, rectification effect, optical switch and spin transition can be implemented at the reduced scale of a chemical group in those nanomaterials.
We are thus interested by studying spin dependent transport phenomena (spintronics) in molecular junctions by using all the potential of molecular electronics. Our first approach consist of using functionnal molecules as, for instance, molecular diode in ferromagnetic metal/molecules/ferromagnetic metals junctions to produce new hybrid spintronic devices and functionnalities. We try also to understand the impact of chemical bonding at the interface between molecules and ferromagnetic metals on spin injection properties.
More complex devices integrating graphene and/or carbon nanotubes are also under investigation.

A recent review about molecular spintronics can be downloaded here.

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