From Single molecule to molecular devices: Application to charge transfer study at the nanoscale
Damien Riedel
Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS,
Univ. Paris Sud, Université Paris-Saclay, F-91405 Orsay, France
11:45am Room 4217 (New Chemistry Building)
There is nowadays a clear context in which electronic components are reaching a scale that will soon require a new understanding of their initial functionality. Indeed, while current active transistors have gates of ~ 4 nm, some recent research shows that it is possible to achieve gates as small as 0.6 nm1. Therefore, several new constraints concerning, for example, heat transfer and electrical consumption will be a challenge for these devices, including those that integrate photoelectronic processes like solar cells. In this context, it is crucial to be able to understand several aspects of these future components, such as electronic switching2 or electronic transport and charge transfer processes at the nanoscale3.
In the first part of my talk, I will present one of our new research platforms dedicated to these aspects. It is based on the formation of an insulating layer on the surface of silicon with CaF2, paving the way for alternative solutions that use NaCl on metal surfaces. The growth of CaF2 on the bare Si(100) surface exhibits two main regimes, one forming a wetting layer, the other resulting from the growth of ribbons of bands. A detailed understanding of these structures at the atomic scale is crucial for the control of the model devices we want to study. In a second part, I will show that it is possible to electronically decouple the molecules adsorbed on this insulating surface and, from there, study the charge transfer processes in molecular dyads. I will then present the first example of an electronically induced charge transfer process in an iron-tetraphenylporphyrin homodyad when assembled in situ. I will then briefly describe preliminary results for other cases, including an heterodyad, and conclude.
1 M. L. Chen et al. A FinFet with one atomic layer channel, Nature Communications, 11, 1205 (2020).
2 M. Yengui, E. Duverger, P. Sonnet, D. Riedel, Nature Communications, 8, 2211 (2017).
3 P. Ramos, M. Mankarious, M. Pavanello, D. Riedel, Probing charge transfer dynamics in a single iron tetraphenylporphyrin dyad adsorbed on an insulating surface, Nanoscale, 10, 17603-17616 (2018).
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