| 학회 | 한국재료학회 |
| 학술대회 | 2013년 가을 (11/06 ~ 11/08, 제주롯데호텔) |
| 권호 | 19권 2호 |
| 발표분야 | B. 나노 재료(Nano Materials) |
| 제목 | Ultrafast terahertz dynamics of atomically-thin two-dimensional materials: graphene and MoS2 |
| 초록 | Two-dimensional materials, such as graphene and MoS2, are attracting significant interests due to the unique physics of its 2D charge carriers, and due to possible applications in e.g. novel ultrafast high-speed electronics. Here, we discuss the ultrafast terhertz (THz) dynamics in these materials, and provide compelling experimental evidence of unusual charge carrier dynamics. In graphene, we show experimental verification of the transient zero-balance of the oscillator-strength sum rule in graphene. By employing both ultrafast terahertz and optical spectroscopy, we directly substantiate that the rapid depletion of the high-energy oscillators near the Fermi edge synchronously and yet precisely complements the transient absorption of the terahertz oscillators [1]. We also present experimental study on the ultrafast refractive index control of graphene-metamaterial devices [2]. In atomically thin MoS2, we investigate the ultrafast pump-probe spectroscopy examining exciton dynamics. Spectrally- and temporally-resolved measurements are performed to investigate the interaction dynamics of two important direct-gap excitons (A and B) and their associated broadening kinetics. The two excitons show strongly correlated inter-excitonic dynamic, in which the transient blue-shifted excitonic absorption originates from the internal A-B excitonic interaction [3]. [1] J. Kim, S. J. Lim, S. J. Chae, I. Maeng, Y. Choi, S. Cha, Y. H. Lee, and H. Choi, “Ultrafast zero balance of the oscillator-strength sum rule in graphene,” Scientific Reports, accepted for publication (2013). [2] S. H. Lee, J. Choi, H.-D. Kim, H. Choi, and B. Min, “Ultrafast refractive index control of a terahertz graphene metamaterial,” Scientific Reports 3, 2135 (2013). [3] S. Sim, J. Park, J.-G. Song, C. In, Y.-S. Lee, H. Kim, H. Choi, “Exciton dynamics in atomically thin MoS2: inter-excitonic interaction and broadening kinetics,” Physical Review B 88, 075434 (2013). |
| 저자 | 최현용 |
| 소속 | 연세대 |
| 키워드 | terahertz; graphene; MoS2 |
