熱化學氣相沉積法成長橫向碳奈米管之電性研究

Electrical characterization of laterally grown carbon nanotube by thermal CVD

陳志豪(Chih-Hao Chen)

指導教授 ： 黃豐元

國立中央大學/工學院/機械工程學系/碩士(2006年)

摘要

本實驗利用化學氣相沉積法(Thermal Chemical Vapor Deposition)成長橫向碳奈米管(Carbon nanotubes, CNTs)於二極元件上，且探討碳源供給型態、載氣型態及成長時間對碳管整合之二極元件的電性影響，並利用參數的控制來達到少根碳管橋接於兩極之間。在載氣中若增加氮氣含量，可有效提高碳管石墨化，但也使碳奈米管成長數量大幅減少，因此在考慮碳管高石墨化下，並得到少根碳管橋接又不至於使元件斷路，選擇含氮量為50%為最佳參數。利用此組參數於三極元件上，並成功在不同間距成長少根碳管懸接，在搭配三條獨立方程式輕易求解出橋接於不同間距中各碳奈米管之內電阻，與碳奈米管/金屬電極接面之接觸電阻，並透過退火步驟，碳奈米管之內電阻變化不是太大，但接觸電阻在連續退火至900℃會有最低值，其值由幾百KΩ下降至十幾KΩ，並且從室溫至40K下作測量電性，可發現碳管電阻值會因為環境溫度下降，而有升高之趨勢，但接觸電阻則無明顯的變化。

關鍵字

碳奈米管 ； 接觸電阻 ； 退火 ； 低溫量測

並列摘要

The objective of this disquisition presented that laterally grown carbon nanotubes (CNTs) on diode devices by thermal chemical vapor deposition (Thermal CVD). Follow growing, the electrical characterization of various parameters including carbon source, carrier gas and grown time on carbon nanotube growth was discussed. Singular or few carbon nantubes were bridged on diode device by controlling the proper parameters. As nitrogen concentration increased, number of bridged CNTs reduced. Addition of N2 enhanced the degree of graphitization of CNTs but the diode device was an open circuit and length of CNTs was shorter at the nitrogen concentration of 60%. The proper nitrogen concentration was 50%. Using the parameter on triode device, it was formed a metal /carbon nanotube /metal /carbon nanotube /metal structure. Contact resistance, Rc , and tow net resistances, RCNT1 and RCNT2, were determined from three equations. In the triode device, the effect of annealing on the resistances of CNT itself was not noticeable. The contact resistance between CNTs and metal electrode could be reduced most after 900 C annealing process. From 40 K to room temperature, resistances of CNTs themselves decreased with temperature while the contact resistance between CNTs and metal electrode remained unchanged.

並列關鍵字

Carbon Nanotube ； Contact Resistance ； Annealing ； Low Temperature Measurement

參考文獻

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