| Time：1120607 (Wed.) 14:20~16:20 Speaker：Prof.林宮玄(Kung-Hsuan Lin) 中央研究院物理研究所/Institute of Physics, Academia Sinica Title：Femtosecond laser microscopy of InSe layered materials Abstract：InSe layered semiconductors with high mobility have advantages over the transition-metal dichalcogenides in certain device applications. Understanding carrier dynamics, especially around the bandgap, is important for fundamental scientific interest and for improving the performance of devices. In the first part of this talk, I will present how we used femtosecond laser microscopy to study ultrafast carrier dynamics in exfoliated InSe nanoflakes. We found that a shrinkage of optical bandgap ~30 meV within 20 ps, attributed to the thermalization of hot carriers via the band-filling effect and bandgap renormalization. In addition, we observed the carrier recombination rate increased when the thickness of InSe nanoflakes decreased, dominated by surface recombination. In the second part, I will report the optical second harmonic generation of strained InSe nanoflakes. We studied angle-resolved second harmonic generation pattern of InSe few-layers under uniaxial strain both experimentally and theoretically. Place：S101, Gongguan Campus, NTNU |
