Saturable Absorption and Ultrafast Carrier Dynamics Study of Topological Insulators

• Main Authors: Hsuan-Yin Chen, 陳宣尹
• Other Authors: Chao-Kuei Lee
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/zd5f8y

碩士 === 國立中山大學 === 光電工程學系研究所 === 104 === In this thesis, carrier dynamics and phonon propagation of topological insulators are investigated using novel pump-probe technique. First, the evolution of carrier dynamics of Bi2Te3 thin films from unsaturated to saturated condition was characterized by extremely low excitation condition. The competition between surface state and bulk state was proposed to interpret the clear trend of which the bulk state will dominate the behavior as decreasing film thickness. Regarding to the phonon propagation of topological insulator Bi2Se3 thin films, a new type of reflective pump probe which the pump and probe beam excite the film on the opposite side was buildup. The result of clear coherent phonon behavior further confirm the conclusion from typical reflective pump probe measurement. Additionally, the result indicated the nature of phonon propagation. Furthermore, thickness dependent of phonon life time and relaxation time are also discussed.