| 학회 | 한국재료학회 |
| 학술대회 | 2016년 가을 (11/16 ~ 11/18, 경주 현대호텔) |
| 권호 | 22권 2호 |
| 발표분야 | G. 나노/박막 재료 분과 |
| 제목 | Ultrafast time-resolved exciton dynamics in 2D materials |
| 초록 | Photogenerated electron-hole pairs in solids create bound states, whose elementary quasiparticle state is called exciton. In transition metal dichalcogenides (TMDs), this is particularly the case as the two-dimensional materials approach a monolayer limit, where the reduced dielectric screening results in a strong Coulomb interaction, leading to an extremely large exciton binding energy. In this talk, I will present our ultrafast optical studies on the exciton dynamics in TMDs. Four recent investigations will be discussed. First, I will show the ultrafast interband spectroscopy on MoS2 to explore the photo-excited exciton broadening kinetics. There, we have seen that the strong interexcitonic interaction causes the linewidth broadening of both A and B excitons [1]. Second, I will discuss our ultrafast optical-pump and optical-probe spectroscopy, performed in the coherently stacked MoS2-WS2 heterostructure. The interlayer excitonic transition and its corresponding interlayer-orientation-dependent exciton dynamics will be discussed [2].Third, I will discuss the mid-infrared 1s-intraexcitonic transition in monolayer MoS2. We observed two-folded 1s→3p intraexcitonic transitions within A and B exciton and the 1s→2p transition between A and B exciton [3]. Finally, I will discuss our recent investigations on the optical Stark effect in ReS2, where the below-gap excited optical Stark effect can be selectively measured in the two anisotropic A and B excitons [4]. References [1] Sim, S. et al. Physical Review B 88, 075434 (2013). [2] Heo, H. et al. Nature Communications 6, 7372 (2015). [3] Cha, S. et al. Nature Communications 7, 10768 (2016). [4] Sim, S. et al. Nature Communications, under review (2016). |
| 저자 | 최현용 |
| 소속 | 연세대 |
| 키워드 | 2D materials; ultrafast spectroscopy |
