The investigation of highly ordered Ag films on mica with STM, LEED and XPS

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/71672

Title:	The investigation of highly ordered Ag films on mica with STM, LEED and XPS
Authors:	劉辰偉;Liu,Chen-Wei
Contributors:	物理學系
Keywords:	銀薄膜;雲母;低能量電子繞射;掃描穿隧式顯微鏡;X光光電子能譜;Ag film;mica;LEED;STM;XPS
Date:	2016-07-27
Issue Date:	2016-10-13 13:29:23 (UTC+8)
Publisher:	國立中央大學
Abstract:	本論文主要研究銀/雲母薄膜系統的特性。我們以電子束蒸鍍的方法，在劈裂 (freshly cleaved) 的雲母片表面蒸鍍不同厚度的銀薄膜，並利用掃描穿隧式顯微鏡 (Scanning Tunneling Microscopy, STM) 、低能量電子繞射儀 (Low Energy Electron Diffraction, LEED) 以及X光光電子能譜術 (X-ray Photoemission Spectroscopy, XPS) 檢測銀薄膜的性質。　　低能量電子繞射的實驗結果中，400 nm、200 nm、100 nm的樣品清潔與加熱後，皆可見一組清晰的(1×1)繞射點，表示此銀薄膜的表面具高度有序的結構且方向一致，與單晶的銀(111)表面類似。掃描穿隧式顯微鏡的結果中，經過清潔與加熱後，可觀察到樣品表面存在400 nm大範圍平坦的平台，平台以外的區域則有許多台階與凹洞。我們也利用掃描穿隧式顯微鏡研究加熱溫度與清潔次數對樣品表面的影響。另外，為了觀察薄膜表面銀原子排列的方向性，我們在表面鍍上鉍原子，觀察鉍原子的排列以推測表面銀原子排列的方向。我們成功地在表面不同區域觀察到(√3×√3)R30°的重構，得知不同區域之銀薄膜表面銀原子排列方向皆為一致。　　為進一步驗證此銀薄膜具有單晶的性質，我們在銀薄膜上進行了矽薄膜成長的實驗。我們重現出(4×4)與(√13×√13)R13.9°等矽烯(Silicene)結構，與銀單晶的實驗結果相符。我們也利用X光光電子能譜術量測乾淨的銀薄膜樣品與鍍上矽之後的樣品表面，藉由分析蒸鍍時不同基板溫度的矽2p與銀3d能譜曲線，得到矽的覆蓋量與蒸鍍時基板溫度的關係。 ;In this study, the Ag thin films of different thickness were grown on freshly cleaved mica. We investigated these thin films with scanning tunneling microscopy (STM), low energy electron diffraction (LEED) and X-ray photoemission spectroscopy (XPS). 　　In the experimental results of 400 nm, 200 nm and 100 nm sample, clear (1×1) LEED pattern was observed after the sample was cleaned by sputtering and annealing. It indicates that the surface of the Ag films are highly ordered with only one orientation, resembling to the Ag(111) single crystal. In the STM results, 400-nm-wide flat terrace was obtained after sputtering and annealing the surface. We also investigated the change of the surface caused by sputtering and annealing. In order to determine the orientation of surface Ag atoms, we deposited Bi on the surface. We observed aligned (√3×√3)R30° reconstruction at different regions on the surface, which means only one orientation on the surface. In the results of Si deposition experiments, the (4×4) and (√13×√13)R13.9° reconstructions were observed. This is the same as the results of the Si deposition on Ag(111) single crystal. Our results demonstrate that the surface of the Ag/mica thin film indeed possesses the surface characteristics of the Ag(111) single crystal.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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