主動式及被動式石墨烯電漿兆赫波波導元件開發

Abstract

本論文透過石墨烯電晶體結構調查化學氣象沉積石墨烯之特性，如狄拉克點、載子遷移率等。並且利用摻雜氧化鈦(TiOx )，及摻雜後照光的方式改變石墨烯費米能階達到調控的目的。此外，使用原子氣相沉積系統製備High-κ 材料薄膜，使閘極氧化層變更薄，應用於石墨烯電晶體上。之後配合本實驗室設計且利用半導體製程所完成製備的石墨烯電漿波導結構。我們將可以透過石墨烯配合光柵奈米結構由特定之頻率激發出表面電漿共振現象。並利用兆赫時域解析頻譜（Terahertz time-domain spectroscopy, THz-TDS）觀察表面電漿共振現象。先前本實驗室由馬克斯威爾方程式出發建立出的表面電漿共振理論模型可得知調變石墨烯費米能階，將會使表面電漿共振穿透率低點產生變化。因此結合兩樣技術，將有機會開發出極具潛力的兆赫波調控元件。

In this thesis, the electrical properties such as Dirac point, carrier mobility of chemical vapor deposited graphene were investigated. Then we fabricate controllable n-type doping graphene transistors by using doping layers of titanium suboxide (TiOx) thin film, and comparing the results with sunlight illumination to those without sunlight. Besides, we fabricate thinner high-κ dielectric gate oxide which acts as a good insulating layer in our devices. By these methods, we change the Fermi energy of graphene. With the graphene surface plasmonic theory, the graphene plasmonic waveguide would be designed and fabricated by semiconductor manufacturing. Through the theory, we know the relation between Fermi energy and frequency of surface plasmon resonance. Finally, we combine method of tuning Fermi energy of graphene with graphene plasmonic waveguide theory to make tunable graphene devices, which may have great potential for use in the future development of active and passive plasmonic device in Terahertz band.