| 摘要: | 本研究中已成功的掌握製程參數並製備出大面積奈米孔洞結構的陽極氧化鋁模板與大範圍的純鎳、鈷金屬及其不同組成比例之合金奈米線陣列。所製備出的陽極氧化鋁模板孔徑大小平均約為25 nm。此外，以直流電電鍍結合市售陽極氧化鋁模板成功製備出純鎳、鈷金屬及其不同組成比例合金（Co:Ni=1:9、Co:Ni=1:1、Co:Ni=9:1）之奈米線。在穿透式電子顯微鏡（TEM）以及選區電子繞射（SAED）的分析，可發現所製備的純鎳及純鈷奈米線分別為多晶FCC及HCP的晶體結構，而三種不同組成成份的鈷-鎳合金奈米線則皆為HCP之單晶結構。純鎳、鈷金屬與其合金奈米線的平均直徑約為250 nm。從能量散佈分析儀（EDS）的線掃描分析顯示，合金奈米線中的鎳鈷組成成份分佈相當均勻。鈷鎳合金奈米線的成長方向經鑑定後分別為:樣品A（Co:Ni=1:9）為[-6241]、樣品B（Co:Ni=1:1）為[-3211]、樣品C（Co:Ni=9:1）為[02-21]。 在電性性質量測分析結果發現，鈷、鎳金屬的添加比例對於鈷鎳合金奈米線的電阻率有很顯著的影響。一開始鈷鎳合金奈米線的電阻率會隨著鈷金屬的添加而增加，當鈷鎳合金奈米線中鈷金屬含量超過鎳金屬時，鈷鎳合金奈米線的電阻率便開始下降，對於此電性結果可用Nordheim定律闡釋。另一方面，實驗中也發現鈷-鎳合金奈米線受外加磁場的影響十分顯著。本研究中利用外加磁場的控制，可成功操控鈷-鎳合金奈米線在矽基材上排列出具有二維方向的陣列圖形。 In this study, the AAO template with large-area nanopores structure and the large-scale well-aligned pure Ni, Co, and Co-Ni alloy nanowires arrays with different composition ratio of Co and Ni were successfully fabricated under controlled processing conditions. The average pore size of the AAO template produced was about 25 nm. On the other hand, pure Ni, Co, and Co-Ni alloy nanowires with different concentration ratios of Co to Ni (Co:Ni=1:9, Co:Ni=1:1, Co:Ni=9:1) were successfully synthesized by DC electrodeposition into nanopores of commercial AAO template. Based on the TEM and SAED analyses, it is found that the Ni and Co nanowires were polycrystalline with FCC and HCP structures, respectively. In addition, the three sets of Co-Ni alloy nanowires were all single crystalline, and these single crystalline Co-Ni nanowire possess a HCP structure. The average diameter of the metal and alloy nanowires was about 250 nm. From the EDS line-scan profiles analysis, it is revealed that alloy nanowires were entirely composed of Co and Ni, and uniform distributions of Co and Ni throughout these nanowires. The growth direction of the Co-Ni alloy nanowires of samples A (Co:Ni=1:9), B (Co:Ni=1:1), and C (Co:Ni=9:1) were identified to be along the[-6241], [-3211], and [02-21] directions, respectively. From electrical property measurement, the addition of Co to Ni could strongly affect the resistivity of Co-Ni alloy nanowires. The resistivity of Co-Ni nanowire was found to increase with the addition of Co to Ni first then decrease. The results are discussed in the context of the Nordheim’s rule. On the other hand, the Co-Ni nanowires were found to be very sensitive to the externally applied magnetic field. In this study, experimental result demonstrated that by applying external magnetic fields, these Co-Ni nanowires can be controlled to align along the directions of applied magnetic filed and assemble into a 2D ordered pattern on Si substrate. |
