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標題: | 利用低溫掃描穿隧電子顯微鏡研究以化學氣相沉積生成的單層二硫化鉬之型態與電性結構 Low Temperature Scanning Tunneling Microscope Investigation of Morphology and Electronic Properties of Monolayer MoS2 Grown by Chemical Vapor Deposition |
作者: | Chi-Hung Luo 羅啟宏 |
指導教授: | 林敏聰(Minn-Tsong Lin) |
關鍵字: | 二硫化鉬,過渡性金屬硫化物,化學氣相沉積,電子穿隧顯微鏡,莫爾條紋,掃描穿隧能譜,狀態密度,針尖誘導的能帶彎曲, Molybdenum disulfide,Transition-metal dichalcogenide,Chemical vapor deposition,Scanning tunneling microscopy,Moire pattern,Scanning tunneling spectroscopy,Density of state,Tip-induced band bending, |
出版年 : | 2013 |
學位: | 碩士 |
摘要: | 二硫化鉬是一個典型的層狀過渡性金屬硫化物的材料系列。我們研究以化學氣相沉積的二硫化鉬成長在高定向熱解石墨表面上。並且利用低溫電子穿隧顯微鏡解析原子結構及型態。而單層二硫化鉬與高定向熱解石墨的不同方位差異,有觀察到不同的莫爾條紋週期性。此外,我們發現當電子穿隧顯微鏡的探針非常接近單層二硫化鉬在熱解石墨表面上時,我們能直接地觀察到底下基板高定向熱解石墨的結構。所以,在某個掃描設定參數範圍裡,二硫化鉬就像電子化透明。並且利用掃描穿隧能譜測量二硫化鉬的狀態密度特徵。狀態密度顯示了單層與多層二硫化鉬的能隙關係,且當厚度越後能隙越小。狀態密度曲線也顯示了一些狀態在二硫化鉬的能隙裡。這現象是由尖誘導的能帶彎曲所引起當電子穿隧顯微鏡探針掃描半導體表面時。 Molybdenum disul de (MoS2) is a typical example from the layered transition-metal dichalcogenide family of materials. We investigated that MoS2 grown on a highly oriented pyrolytic graphite (HOPG) surface by chemical vapor deposition (CVD). We resolved the atomic-scale structure and morphology with low temperature scanning tunneling microscopy (LT-STM). Di erent periodicities in the moir e patterns are observed corresponding to orientation di erence between monolayer MoS2 and HOPG. Besides, we discovered that when the STM tip is very close monolayer MoS2 on HOPG, we could observe the structure of HOPG, directly. The MoS2 is electronically transparent in a certain setpoint range. Scanning tunneling spectroscopy (STS) was used to measure characteristics of density of state (DOS) of MoS2 . The DOS shows the band gap of monolayer and multi-layer, which would be reduced when the layer is getting thicker. The DOS curve also shows some peaks inside the band gap of MoS2. This phenomenon results from tip-induced band bending (TIBB) when STM tip scans the semiconductor surface. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/17644 |
全文授權: | 未授權 |
顯示於系所單位: | 物理學系 |
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