Molecular electronics (ME) has shown serious potential as a complementary or even alternative technology to contemporary semiconductor-based microelectronics . However, the time scale of relevant electronic and vibronic processes in the molecule incorporated into an electrical circuit is on the order of picoseconds and shorter, thus time-resolved investigations of promising ME systems/architectures directly with electronic circuitry are not possible. Therefore, novel methods for probing of the electronic states of a molecule placed between two metal contacts in-situ are needed. This is achievable exploiting a process of hot-electron generation in localized, optically induced plasmonic fields . Since the lifetime of these hot-electrons is on the order of hundreds of femtoseconds it is possible to use them to trace the picosecond scale dynamics taking place in a molecular junction .
During this doctoral research program a series of experiments with laser illuminated junctions will be performed. The generation of plasmonic field and subsequent creation of hot-electrons will be characterized in the junction by measuring the I-V characteristic through a reference molecule. This will allow to establish experimental conditions for a pump-probe experiment that will provide the temporal dimension of measurements. Finally, the pump-probe experiments will be performed to study the influence of molecular composition on the electronic dynamics in the junction.
The doctoral candidate would learn operating ultrafast laser technology and will get familiar with fundamental techniques related to them. Amongst them one can name: Scanning tunneling microscopy, frequency resolved optical gating, photoelectron spectroscopy, non-linear optical harmonic generation, pump-probe spectroscopy. The candidate will receive a deeper insight into molecular physics and nanoplasmonics technology as she/he is going to propose own optoelectronic components and use techniques to test them. Application and testing of mathematical models goes in hand with the evaluation of the experimental work, therefore the candidate will understand in detail the theoretical aspects of the studied topics as well. Overall, the candidate would have the opportunity to develop and realize own experiments in order to pursuit the set up goals which will lead to his independence in research.
1. J. K. McCusker, "Electronic structure in the transition metal block and its implications for light harvesting," Science (80-. ). 363, 484–488 (2019).
2. H. Reddy, K. Wang, Z. Kudyshev, L. Zhu, S. Yan, A. Vezzoli, S. J. Higgins, V. Gavini, A. Boltasseva, P. Reddy, V. M. Shalaev, and E. Meyhofer, "Determining plasmonic hot-carrier energy distributions via single-molecule transport measurements," Science (80-. ). 369, 423–426 (2020).
3. R. Arielly, N. Nachman, Y. Zelinskyy, V. May, and Y. Selzer, "Picosecond time resolved conductance measurements of redox molecular junctions," J. Chem. Phys. 146, (2017).
University grade training in physics topics. Enthusiasm in physics and science required. Experience with work in a physics laboratory is an advantage, but not required.