Ultrafast Dynamics of Te-doped InSb Studied by Time-Resolved Femtosecond Spectroscopy

• Main Authors: Wu, Siang-Lu, 吳祥祿
• Other Authors: Luo, Chih-Wei
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/75821324593483084175

碩士 === 國立交通大學 === 電子物理系所 === 100 === In this dissertation, we used time-resolved femtosecond spectroscopy to study the ultrafast dynamics of Te-doped InSb with various doping electron concentration. The relaxation time of photoinduced quasiparticles was determined by fitting the relaxation process of ?嵇/R at various ambient temperatures and with various pump fluences. According to two-temperature model, the electron-phonon coupling constant of InSb could be further estimated from the relaxation time obtained from ?嵇/R, which strongly correlates to the number of the effective free carriers in InSb caused by optical pumping or thermal excited carriers. The electrical properties of InSb were studied by temperature-dependent Hall measurements and resistance experiments. The resistivity of heavily doped InSb represents the metal-like behavior. Surprisingly, a metal-insulator phase transition was clearly observed around 170 K in intrinsic InSb. Moreover, the shifts of plasma edges were observed by the temperature-dependent infrared reflectivity spectrum. According to Drude-Lorentz model, the plasma frequency could be obtained by fitting the infrared reflectivity spectrum. The electron effective mass, electron momentum scattering time and electron-phonon coupling constant could be calculated from the fitting parameters. The electron and phonon temperature discontinuity in the PANTEC structure was clearly observed by the time-resolved pump-probe microscope. The carrier relaxation process was changed from interband electron-electron scattering to electron-phonon scattering as increasing the pumping fluence near the interface of PANTEC structure.