Investigation of Optical Absorption and Thermal Transport in Suspended Carbon Nanotube Bundles

論文發表人: 許易凱 (南加州大學材料所博士班)

 

http://meetings.aps.org/Meeting/MAR09/Content/1369

 

在本實驗中, 我們結和拉曼光譜與架在奈米碳管兩側微米制程的電阻溫度探測器來測量奈米碳管對於雷射光加熱吸收的能力.  根據熱傳導的路徑, 碳管從雷射加熱點所吸收的熱會等於熱從加熱點到左右兩端的總量也會相等於電阻溫度探測器所偵測到的總熱能量. 實驗所用的碳管直徑從 7.1-8.2奈米, 長度從11.7-14.3微米而我們用單一波長532nm 雷射在碳管中間點加熱. 實驗結果顯示出 0.03％-0.44％ 的雷射能量可以被碳管所吸收.  藉著測量加熱點與碳管兩側的溫度, 碳管的熱導系數也可以得到. 在此碳管在雷射加熱點的溫度則是由觀察拉曼光譜位移所得到. 

 

The optical absorption in suspended carbon nanotube (CNT) bundles is measured using Raman spectroscopy and two platinum resistance thermometers (PRTs), located at both ends of the suspended CNTs. The power absorbed from an incident focused laser is determined from the thermal power flowing through both ends of the CNT, detected by resistance changes in the PRTs. The results show 0.03 to 0.44％ absorption of a focused 532nm laser with a 0.4 mm diameter spot size incident on CNT bundles with diameters and lengths varying from 7.1-8.2nm and 11.7-14.3 mm, respectively. The thermal conductance of the suspended CNT bundles can also be obtained by measuring the temperature difference between the incident laser spot and both ends of the suspended CNT. Here, temperatures in the center of the nanotube are extracted from the temperature-induced downshifts of the G band Raman mode.