不同基板上成長奈米螺旋碳管對於電磁波吸收性質之研究

Abstract

本論文主要是針對奈米螺旋碳管在不同基板上的成長，對其電性的量測方面的應用做相關的研究與討論。本論文改良以往的成長技術，不同於以往在矽晶片上成長奈米螺旋碳管，在此論文中準備了銅網、不鏽鋼網、鋁箔、銅箔以及棉布和紙當作成長的基板，利用鐵與錫二元素組成的催化劑塗抹在不同基板上，藉由單段高溫爐之化學氣相沉積法成長奈米螺旋碳管，成功地在低價的基板上大量成長的奈米螺旋碳管。接著將已成長完的試片利用護貝膠膜直接包覆起來製成量測薄片，探討在相同濃度的催化劑下對不同基板上成長奈米螺旋碳管，量測並觀察其電磁波吸收率之影響。 其測量的電磁波範圍主要在18~75 GHz，發現在成長過後的試片對電磁波阻隔有明顯之提升。此外，為了量測出奈米螺旋碳管在低頻率(1~18 GHz)下對電磁波吸收之影響，特別製作了以紙當成長基板成長奈米螺旋碳管的電磁波吸收試片，成功的量測出電磁波吸收率達到-30 dB (吸收率超過99.9 %)，此外，若當試片疊加至三層時，電磁波吸收效果可達到-49 dB(26 GHz)。

The study focuses on the growth of carbon nanocoils on different substrates and the results of its electrical measurement. Refining the traditional growing method, it grows carbon nanocoils on the silicon chip. The study provides various substrates ranging from copper grid, stainless steel meshes, Al foil, Cu foil, cotton and papers. It coats catalyst which composed of Fe and Sn on those various substrates. Then, the researcher grows carbon nanocoils with single_zone temperature CVD. With the refined method, a great amount of carbon nanocoils grows on the low-cost substrates. Finally, in order to measuring electromagnetic wave absorption, the specimen is covered with laminating film. It aims at probing the influence of electromagnetic wave absorption on the same catalytic concentration with different substrates. The measuring electromagnetic waves mainly range from 18 GHz to75 GHz. The study finds out that the shield of grown specimen has significantly improved to electromagnetic waves. In addition, in order to measure the electromagnetic wave absorption in low frequency (1~18 GHz) affected by carbon nanocoils, the study particularly use paper as substrate. The result shows the electromagnetic wave absorption of paper substrate reaches -30 dB (absorption rate 99.9 %). Furthermore, it can reach -49 dB (26 GHz) by tripling the layers of the specimen.