奈米碳管之結構與應用物理特性研究

Abstract

奈米碳管，因為具有極佳的高寬比、小的曲率半徑、良好的化學穩定性、以 及很高的機械強度，奈米碳管表面的幾何形狀，具耐高電流密度、高導電度等等， 被廣為應用在元件上。本計劃利用熱化學氣相沉積系統以鎳為催化層，由控制奈 米碳管成長的參數來合成不同形態的奈米碳管，以求得最佳合成參數。為進一步 瞭解奈米碳管在電子傳導之功用，預計以電子束微影製程得到奈米級的結構尺度 製作多層次結構並研究不同製程中，電漿處理用以改變奈米碳管表面之結構以提 高導電之特性。實驗中，預計發展橫向奈米碳管之電路整合，將鎳觸媒借由預設 多層次鍍層設計，使最上層之鉭金屬扮演防止奈米碳管垂直成長的功能，製程中 以熱化學氣相沉積系統合成奈米碳管，引導碳管橫向連接到兩端鈦金屬電極，電 漿後處理之橫向碳管在電性與化性分析上，以X 光電子能譜儀分析表面化學機 制，表面形貌以掃瞄式電子顯微鏡與原子力顯微鏡觀察，奈米碳管結構以穿透式 電子顯微鏡觀察，電漿後處理後之奈米碳管以介電層披覆，使用電性量測系統探 討碳管橫向的電性與物理性質，此結構未來可運用在奈米碳管場效電晶體。此 外，結合了原子力顯微鏡與分子動力學模擬來分析奈米碳管之奈米力學機制。藉 由此研究，將更精確地瞭解奈米碳管之結構與機電特性，進而提升光電與半導體 之技術。

Carbon nanotubes (CNTs) have applied for the process of devices, because of their high aspect ratio, small radius curvature, high chemical stability and high mechanical strength. CNTs arrays depend strongly on the work function and geometry of the surface of CNTs arrays, which have excellent properties for application. The research was to develop an Integrated Circuit compatible process to grow the horizontally-oriented multiwalled carbon nanotubes (MWCNTs) across the trenches of the catalytic metals on pre-defined titanium (Ti) electrodes by means of the thermal chemical vapor deposition was investigated. The Ti, as the upper layer on Ni pads, not only plays a role as a barrier to prevent vertical growth but also serves as a buffer site that helps in forming smaller nano-sized Ni particles. The information about interface structure of the lateral MWNTs will be detecting by X-ray photoelectron spectroscopy (XPS) after plasma treatment. The CNT is characterizing by field-emission scanning electron microscopy (FES-EM), atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). The electrical property of the MWNTs exposure to plasma will be analysis using I-V system in SiO2 coved. Also, these structures can be applied to field-effect transistors applications. In addition, the nanomechanics of CNTs are analyzed by the combination of AFM and Molecular Dynamics Simulations, further promoting the optoelectronics and semiconductors techniques.