銅鎳合金系統製備大面積石墨膜之研究

The Study of Large Area Graphite Film Preparation Based on Cu-Ni Alloy System

吳亭瑩(Ting-Ying Wu)

指導教授 ： 徐開鴻

國立臺北科技大學/工程學院/材料及資源工程系研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00487

摘要

石墨烯是由碳原子排列成蜂窩狀的二維結構，具有許多特性，如高機械應力、高熱傳導係數、高指向的表面，以及快速的遷移率。石墨烯有許多用途，例如可製備出單電子電晶體、透明電極、紫外線LED、氣體感測、超級電容以及生物晶片。
本研究利用高溫高壓合成鑽石中過渡金屬對碳原子催化之原理，選擇銅及鎳過渡金屬進行試驗，碳來源採用石墨粉，在高溫真空狀態下，使銅鎳合金到達液相狀態時，石墨因過渡金屬液相催化的機制下自我修復重組，在合金表面上成長出石墨膜。透過改變合金及石墨的比例、持溫的時間，在最佳的參數下，可以成功的製備出連續狀且大面積(公分)的石墨膜。
本實驗分成三個部份做研究探討：(1) 配比探討–碳含量以1 wt%與0.5 wt%分為兩組實驗組，搭配不同的金屬配比，發現在C : Cu-Ni(30-70)=1 wt% : 99 wt%，以及C : Cu-Ni(50-50)=0.5 wt% : 99.5 wt%時，可以獲得最佳的連續狀石墨膜。此外，由光學顯微鏡(Optical Microscope, OM)與掃描式電子顯微鏡(Scanning Electron Microscope, SEM)的觀察，了解本實驗的成長機制主要是因固溶析出的石墨片以及石墨粉末受液態合金擾動拆解出的片狀石墨，由於比重的差異與液態合金催化機制，在高溫時會在表面形成連續石墨膜。 (2)不同持溫時間探討–當持溫時間為5小時，石墨膜擁有較佳的連續性及電性。(3) 熱氧化減薄處理觀察–在熱處理溫度500℃、持溫時間1小時，石墨膜厚度減少，而石墨膜仍維持連續性，且電性仍維持熱處理前的水準，為本次實驗最佳熱處理參數。

關鍵字

石墨烯 ； 高定向熱解石墨 ； 液相催化

並列摘要

Graphene is a two-dimensional crystal of carbon atoms arranged in a honeycomb lattice, it has high mechanical strength, high thermal conductivity, high specific surface area, and high electron mobility. Graphene is the ideal material for many dream applications, such as single electron transistors, transparent electrodes, UV light emitting diodes, gas sensors, super capacitor and biochips.
This study is based on the mechanism of transition metal catalyzed graphite to diamond transition under high pressure and temperature. Copper and nickel transition metal powders are adopted to react with graphite powders in high temperature vacuum sintering furnace. After melting, the graphite flakes can be catalytically mended together by the transition metal alloy. This process is self assembling and self healing, so graphite layers can be formed on the surface of the ingot. With optimal alloy/graphite ratios and holding time, large area graphite film can be successfully prepared.
The experiment consists of three parts: (1) Ratio - The ratios of C : Cu-Ni(30-70)=1 wt% : 99 wt%, and C : Cu-Ni(50-50)=0.5 wt% : 99.5 wt% are optimal. Besides, in view of the graphite film forming mechanism, graphite powder is first precipitated and separated by melting alloy then assembled as flakes in the melting alloy. After that, graphite flakes are transformed into graphite film on the surface of alloy ingot as a result of catalytic conversion process and density difference. (2) Various holding time – We observed the best character of graphite films under the condition of five-hour holding time. (3) Heat treatment – The best heat treatment temperature is 500℃ and hold for 1hr .

並列關鍵字

graphene ； HOPG ； liquid-phase catalysis

參考文獻

[2] H. W. Zhu, J. Q. Wei, K. L. Wang and D. H. Wu, “Applications of carbon materials in photovoltaic solar cells”, Solar Energy Materials and Solar Cells, vol. 93, 2009, pp. 1461-1470.

[10] J. A. Libera and Y. Gogotsi, “Hydrothermal synthesis of graphite tubes using Ni catalyst”, Carbon, vol. 39, 2001, pp. 1307-1318.

[12] A. K. Geim, “Graphene: Status and Prospects”, Science, vol. 324, 2009, pp. 1530-1534.

[19] S. Banerjee, M. Sardar, N. Gayathri, A. K. Tyagi and B. Raj, “Conductivity landscape of highly oriented pyrolytic graphite surfaces containing ribbons and edges”, Physical Review B, vol. 72, 2005, pp. 075418-1 to 075418-7.

[20] Y. Zhang, J. P. Small, W. V. Pontius and P. Kim, “Fabrication and electric-field-dependent transport measurements of mesoscopic graphite devices”, Applied Physics Letters, vol. 86, 2005, pp. 073104-1 to 073104-3 .