(Invited) Plasmon and Polaritons in Two-Dimensional Molybdenum Compounds
Authors: Kalantar-Zadeh Kourosh 
Published: December 2020

Plasmonics and polarotonics of two dimensional (2D) materials have attracted significant attention due to their desirable dispersion relation. Regarding plasmons, according to the 2D dispersion equation, the cutoff frequency limit can be eliminated. Additionally, their large tuneability, high doping (ultradoping) range, and the existence of favorable depolarization factors allow for their better control. Among 2D materials, molybdenum disulfides and molybdenum oxides have recently received increased attention.1-5 The polariton propagation has also been recently shown in atomically smooth molybdenum oxides. For plasmonic propagatrions, tunable plasmon resonances in suspended 2D molybdenum oxide and molybdenum sulfide flakes are demonstrated. The 2D configuration generates a large depolarization factor and the presence of ultra-doping produces visible-light plasmon resonances. The ultra-doping process is conducted by reducing the semiconducting 2D molybdenum trioxide flakes using simulated solar irradiation. The generated plasmon resonances are controlled by the doping levels and the flakes’ lateral dimensions, as well as by exposure to model proteins and enzymes. It is also possible to reach ultradoping levels. Alternatively, by electrochemically intercalating lithium into 2D molybdenum disulfide nanoflakes, plasmon resonances in the visible and near UV wavelength ranges are achieved. These plasmon resonances are controlled by the high doping level of the nanoflakes after the intercalation, producing two distinct resonance peak areas based on the crystal arrangements. The system is also benchmarked for biosensing using bovine serum albumin. The talk will provide the foundation for developing future 2D molybdenum sulphide and oxide based biological and optical units. Polaronic propagation in full stoichiometric molybdenum oxides will also be discussed.6

References

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2018, 28, 1706006.

2 Wang, Y.; Ou, J. Z.; Chrimes, A. F.; Carey, B. J.; Daeneke, T.; Alsaif, M. M. Y. A.; Mortazavi, M.; Zhuiykov, S.; Medhekar, N.; Bhaskaran, M.; Friend, J. R.; Strano, M. S.; Kalantar-Zadeh, K., Nano Letters
2015, 15, 883-890.

3 Ma, W.; Alonso-González, P.; Li, S.; Nikitin, A. Y.; Yuan, J.; Martín-Sánchez, J.; Taboada-Gutiérrez, J.; Amenabar, I.; Li, P.; Vélez, S.; Tollan, C.; Dai, Z.; Zhang, Y.; Sriram, S.; Kalantar-Zadeh, K.; Lee, S. T.; Hillenbrand, R.; Bao, Q., Nature
2018, 562, 557-562.

4 de Castro, I. A.; Datta, R. S.; Ou, J. Z.; Castellanos-Gomez, A.; Sriram, S.; Daeneke, T.; Kalantar-zadeh, K., Advanced Materials
2017, 29, 1701619.

5 Alsaif, M. M. Y. A.; Latham, K.; Field, M. R.; Yao, D. D.; Medhekar, N. V.; Beane, G. A.; Kaner, R. B.; Russo, S. P.; Ou, J. Z.; Kalantar-Zadeh, K., Advanced Materials
2014, 26, 3931-3937.

6 Ma W.; Alonso-González, P.; Li, S.; Nikitin, A.W.; Yuan, J.; Martín-Sánchez, J.; Taboada-Gutiérrez, J.; Amenabar, I.; Li, P., Vélez, S.; Tollan, C.; Dai, Z.; Zhang, Y.; Sriram, S.; Kalantar-Zadeh, K.; Lee. S-T., Hillenbrand, R.; Bao, Q. Nature
2018, 562, 557-562.