本論文中研究及討論所謂的〖(√3×√3)〗_si 矽烯的表面原子結構。〖(√3×√3)〗_si 矽烯是普遍所認知的多層結構的矽烯。實驗的方法利用氘原子吸附於〖(√3×√3)〗_si 矽烯薄膜，並且使用低溫掃描式穿隧顯微鏡 (STM) 觀察改變過後的薄膜。本論文實驗結果為以下：(1)氘原子吸附後形成了一維的氘/矽長鏈狀的結構。氘/矽長鏈結構是隨機以三個銀[101 ̅] 方向排列，且間距為兩倍的矽(111)晶體的晶格常數。(2)某種原子於氘原子吸附於〖(√3×√3)〗_si 矽烯時被驅逐出來並堆積成有特定晶形的島狀結構。經過統計，發現島狀結構彼此間的高度差恰為銀原子層的高度差(0.24 nm)，STS能譜量測於這些島狀結構發現了Coulomb blockade effect週期性的波峰。因此此種原子被確認為銀原子。上述的這兩點特性與Oura等人所研究的氫/(√3×√3)銀-矽(111)系統十分相似，該系統的氫(氘)/矽長鏈結構方向、間隔相同、銀原子也被驅逐出原本的表面形成銀島。我們的實驗結果與先前Shira等人所提出的銀原子置上模型相符。總言之，我們認為所謂〖(√3×√3)〗_si 矽烯實際上是表面覆蓋著銀原子的矽(111)薄膜，而非二維結構的矽烯層狀的堆疊。

This thesis reports and discusses the atomic structure of the (〖√3×√3)〗_si silicene surface. This surface structure is common to all so-called multi-layer silicene film. Our experimental approach is to expose the (〖√3×√3)〗_si silicene film with deuterium atomic beam and to observe the resulting film morphology by low-temperature scanning tunneling spectroscopy (LT-STM). The experiment results reveal that deuterium is absorbed on Si atom to form one-dimension D/Si chains, which are randomly aligned in three of Ag [101 ̅] directions. The separation of these D/Si chains is 2a, where “a” is the lattice constant of Si (111) crystal, 3.84 Å. Some atoms are expelled from (〖√3×√3)〗_si silicene surface and form 3D islands. The height difference of these 3D islands are an integer multiple of Ag (111) step height. The corresponding STS spectra measurement on the islands show the Coulomb blockade effect. Therefore, that atoms forming the 3D islands are verified as Ag. The surface morphology after deuterium adsorption on the “multilayer silicene” is highly similar to that of H/(√3×√3)Ag-Si (111) studied by Oura et al. These findings imply our experiment result is compatible with the Ag-on-top model claimed by Shirai et al.. In summary, we found the so-called multilayer silicene should be rectified as (〖√3×√3)〗_si Si(111)/Ag (111). In the other words, the so-called (〖√3×√3)〗_si silicene is likely an ultra-thin Si (111) film with Ag on its surface.

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