- 學位論文
Thin-film growth of Bi and S on Au(100) studied with LEED and XPS
Thin-film growth of Bi and S on Au(100) studied with LEED and XPS
摘要
本論文中，我們在超高真空的環境下分別透過固態電化學的方式製造硫分子，以及電子束加熱的方式產生鉍原子，並在金(100)表面上進行硫和鉍的薄膜成長，再利用低能電子繞射和X光光電子能譜術來研究金(100)表面上的薄膜成長結構變化以及硫和鉍之間束縛能的變化。鍍鉍在金上的實驗中，我們可以觀察到(1×1)、四個一組的繞射點結構和類似c(4×2)的結構；而透過反覆交替的鍍鉍和曝硫的實驗，最後我們可以從低能電子繞射上觀察到12個圍成圓環的繞射點的有序結構，我們可以從軟體的模擬來確認是一種六方型的結構。透過X光光電子能譜術我們認為這種有序結構中的鉍有兩種電子組態；硫的部分則是藉著束縛能強度來進行數量的估計，最後我們認為單位晶胞內可能會有兩種情況，分別是存有兩顆硫兩顆鉍或是兩顆硫三顆鉍。當這種有序結構加熱至350℃後會崩潰。另外，隨著反覆交替鍍鉍和曝硫的同時，我們透過觀察樣品表面的繞射點化及S 2p、Au 4f和Bi 4f的變化，另外也提出硫和鉍在金(100)面上的成長方式。
並列摘要
The thin-film growth of S and Bi on a clean Au(100)-(5×20) surface was investigated with X-ray photoelectron spectroscopy (XPS) and low energy electron diffraction (LEED). Sulfur(S2) molecules were generated by electrochemical decomposition of Ag2S, and Bi was deposited by electron beam heated evaporator. As the increase of deposition time, Bi on Au(100) forms (1×1), 4-diffraction-point and c(4×2)-like reconstructions. The repeatedly deposition of Bi and S on Au(100) ended up with 12 ordered diffraction points. The ordered structure observed by LEED was identified as a hexagonal structure in real space, and the XPS study of Bi 4f from ordered structure revealed the presence of 2 components. Besides, the amount of S was estimated by the intensity of S 2p. As a result, we infered that there were 2S and 2Bi or 2S and 3Bi in one unit cell. Combining the process of the deposition of S and B, the growth model for S and Bi on Au(100) was proposed.