Transient optical reflectivity in MoSe2 under 785 nm and 810 nm pump excitation

Authors

  • Semmi Takamizawa Graduate School of Pure and Applied Sciences, University of Tsukuba, Japan
  • Yuta Komori Graduate School of Pure and Applied Sciences, University of Tsukuba, Japan
  • Takumi Fukuda Graduate School of Pure and Applied Sciences, University of Tsukuba, Japan
  • Manaka Kawamura Graduate School of Science and Engineering, Saitama University, Japan
  • Keiji Ueno Graduate School of Science and Engineering, Saitama University, Japan
  • Muneaki Hase Faculty of Pure and Applied Sciences, University of Tsukuba, Japan
  • Jessica Afalla Faculty of Pure and Applied Sciences, University of Tsukuba, Japan

Abstract

Transition-metal dichalcogenide (TMDC) crystals have emerged as a new class of two-dimensional materials. TMDCs exhibit strong Coulomb interaction (EB=50−500 meV), and at monolayer thicknesses, can exibit exotic valley- and spin- dependent optical selection rules. The TMDC MoSe2 is semiconducting at room temperature, with a bulk bandgap of ~1.10 eV, and forms ground state A-excitons at its K-point (~1.6 eV). In this report, we present transient reflectivity measurements at 785 nm (1.57 eV) and 810 nm (1.53 eV) optical excitation of bulk MoSe2. A signal inversion of the optical reflectivity was observed with wavelength. When excited near-resonance, the transient reflectivity shows no dependence on fluence and decay times are observed to be longer than the non-resonant case. When excited non-resonantly, a clear fluence dependence is observed in the excitation and decay dynamics. The difference is attributed to the possible formation of A-excitons.

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Published

2021-09-24

Issue

2021: Proceedings of the 39th Samahang Pisika ng Pilipinas Physics Conference

Section

Condensed Matter Physics and Materials Science

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How to Cite

[1]
“Transient optical reflectivity in MoSe2 under 785 nm and 810 nm pump excitation”, Proc. SPP, vol. 39, no. 1, pp. SPP–2021, Sep. 2021, Accessed: Mar. 31, 2026. [Online]. Available: https://proceedings.spp-online.org/article/view/SPP-2021-2F-02