氧化鋅奈米柱在兆赫波段之導電率和光學常數之探討及其應用

Abstract

本研究利用兆赫波時域光譜來研究氧化鋅奈米柱結構的透射率，進而去計算出不同水熱生長環境製成氧化鋅奈米柱複介電系數、光導率、進而使用德魯德史密斯模型得出氧化鋅材料的遷移率和兆赫波電導率。 本論文使用水熱法成長氧化鋅奈米柱陣列，並使用光電導天線配置的兆赫波時域光譜對材料進行解析。飛秒雷射被分束器分成泵浦光束和探測光束，兩者都透過物鏡聚焦在光電導偶極子天線上，泵浦脈衝激勵光電導天線中的載流子，然後我們使用拋物面鏡來準直兆赫波並聚焦在樣本上，最後利用另一對拋物面鏡收集兆赫的透射率。 最後使用計算軟體求得材料的複介電系數、光導率和遷移率、並且比較不同水熱生長時間下的氧化鋅奈米柱對兆赫波時域光譜的影響。

In this study, we use terahertz time-domain spectroscopy to figure out the transmittance of zinc oxide nanorods structure, and then calculate the complex dielectric coefficient, and use Drude-Smith model in different hydrothermal growth condition. The model derives the mobility of the zinc oxide mobility and the terahertz conductivity.

In this thesis, a hydrothermal method is used to grow a zinc oxide nanopillar array, and the material is analyzed using terahertz time-domain spectrum of a photoconductive antenna configuration. The femtosecond laser is split into a pump beam and a probe beam by a beam splitter, both of which are focused by an objective lens on a photoconductive dipole antenna. The pump pulse excites the carriers in the photoconductive antenna, and then we use a parabolic mirror to the direct megahertz wave is focused on the sample, and finally another pair of parabolic mirrors are used to collect the terahertz transmittance.

Finally, the complex dielectric coefficient, light conductivity and mobility of the material were obtained using the calculation software, and compared the influence of the zinc oxide nanorods in different hydrothermal time on the time-domain spectrum of the terahertz wave.