利用反射式高能電子繞射儀分析電沉積在鉑(111)電極上的鈷/鎳薄膜晶體結構

NCU Institutional Repository > 理學院 > 化學研究所 > 博碩士論文 > Item 987654321/58558

請使用永久網址來引用或連結此文件: http://ir.lib.ncu.edu.tw/handle/987654321/58558

題名:	利用反射式高能電子繞射儀分析電沉積在鉑(111)電極上的鈷/鎳薄膜晶體結構
作者:	蔡昇峰;Tsai,Sheng-Feng
貢獻者:	化學學系
關鍵詞:	高能電子繞射儀;掃描穿隧式電子顯微鏡;金屬薄膜;鈷;鎳;RHEED;STM;Cobalt;Nickel
日期:	2012-11-08
上傳時間:	2012-12-25 13:34:56 (UTC+8)
出版者:	國立中央大學
摘要:	本研究以電化學方法沉積鈷/鎳金屬在鉑(111)電極上後，再將鉑(111)電極轉移進行RHEED繞射實驗，對照本實驗室先前in-situ STM圖像的研究結果，綜合討論出鈷/鎳薄膜的薄膜成長方式以及薄膜的晶體結構。在低覆蓋度1~2層鈷膜的情況時，鈷原子會以(111)面的排列方式吸附在鉑(111)面上，而且鈷(111)面中的原子成長方向為[-110]方向角，這與載體鉑(111)面的[-110]方向角相同，而電沉積上鈷原子傾向以自身的晶體結構(FCC,aCo=3.544Å)排列在鉑(111)電極之上，因外，我們還可以從RHEED圖中觀察到氧化鈷，而氧化鈷中鈷原子的間距為3Å，這與過去文獻氧化鈷單晶的鈷原子距離(3.01 Å)相符合，而氧化鈷中的鈷原子[-110]原子成長方向與載體鉑(111)電極相同；隨著鈷膜覆蓋度的增加，2~3層的鈷膜即可以在鉑(111)電極表面上觀察到twin結構的鈷金屬，而高覆蓋度鈷膜的三維晶格繞射點，可以在倒空間可排列出一個BCC的結構，而轉換成物理空間則為FCC晶體結構；這證明了鈷金屬沉積在鉑(111)電極表面時，鈷膜不傾向以自然界鈷金屬最穩定的HCP晶格結構排列，而是傾向以鈷(111)面FCC晶體結構成長在鉑(111)電極表面上。Ultrathin films of cobalt were electrodeposited onto a well-ordered Pt(111) electrode and were transferred into ultrahigh vacuum chamber to be characterized by reflection high-energy electron diffraction (RHEED) techniques. The morphology of these Co thin films was also investigated by in-situ STM. At a sub-monolayer coverage both pseudomorphic cobalt and bulk-like Co(111) adlayers are formed on the bare Pt(111) surface. The former tends to align itself with its [110] axis in parallel to the Pt[110] direction. The first Co (111) layer grows with the in-plane lattice constant of bulk Co and the close-packed atomic rows are aligned with its [110] axis in the Pt[110] direction. In addition, two cobalt oxide domains rotated by 30o with respect to each other are identified with an estimated interatomic spacing of 3 ?, which agrees well with that (3.01 ?) of the crystalline (111) plane of CoO whose [110] directions are aligned in the Pt[110] direction. Co twin nuclei were detected at 2-3 ML Co layers on Pt(111) by RHEED for the first time, and the deduced bcc reciprocal lattice with the fcc-related twin spots of bulk Co strongly provides evidence that Co grows with a fcc (111) rather than a hcp (0001) orientation on Pt(111).
顯示於類別:	[化學研究所] 博碩士論文

文件中的檔案:

檔案	描述	大小	格式	瀏覽次數
index.html		0Kb	HTML	467	檢視/開啟

在NCUIR中所有的資料項目都受到原著作權保護.

社群 sharing

資料載入中.....