矽、金屬矽化物及氧化銦奈米結構之研究

Investigation on Si, Metal Silicide and Indium Oxide Nanostructures

辛正倫(Cheng-Lun Hsin)

指導教授 ： 陳力俊

國立清華大學/工學院/材料科學工程學系/博士(2008年)

https://doi.org/10.6843/NTHU.2008.00154

摘要

研究論文摘要
第一部份，透過場發射掃描式電子顯微鏡內建多探針操作系統，我們成功地定性定量分析單根矽奈米線的機械性質，觀測材料在奈米尺度下所展現出與巨觀塊材差異的特性。奈米線具有異常的韌性及可撓性，其可承受應變量遠超過塊材值，此部份實驗值與理論計算值相吻合，然而矽奈米線之彈性模量值與塊材相當，並未改變，唯彈性常數值大幅下降，但即使在大範圍位移之下，其彈性常數值並未改變。
透過臨場觀測超高真空穿透式電子顯微鏡，我們觀察到鈦矽化物奈米柱在矽鍵結雙晶表面上之成長動力學。在矽鍵結雙晶表面上差排間距小時，成長之奈米柱受到應力場的影響，呈現階梯式的成長，且奈米柱之外形受到應力場局限，然而在差排間距大時，則無法觀測到奈米柱階梯式的成長。
我們成長出氧化矽包覆之鈷矽化物奈米電鑬，並詳細討論其耐熱性及電性。在耐熱性方面，其相較於單純鈷矽化物奈米線，其耐熱可承受溫度可增加500 ℃以上，在電性實驗方面結果證明出晶格缺陷對電阻率的影響，相較於晶格缺陷較高的薄膜而言，其電阻率較低，但比毫無缺陷理論值略高。
第二部份，我們專門討論氧化銦奈米結構合成製作、改質及其特性分析。其中包含了下面四個主題: (1)利用化學氣相沉積法在一高溫化學沉積爐內，來合成高品質氧化銦奈米結構，(2)利用氣-液-固相變化成長方式，利用催化劑促使奈米線的成長，成長出來的氧化銦奈米線具有適當的化學組成成份及結構，透過其他雷射激發，氧化銦奈米線發出的光趨近單色，且可以發出紫外光線，並利用調控鋅(Zn)的有效摻雜，可使原發出的紫外光改發出可見光--綠光，達到氧化銦奈米線光致螢光特性調變的目的，使奈米線的發光特性有與日後光電產業結合的可能性，(3) 矽基材上首先製做出高密度、具有優選方向性的氧化銦奈米環結構，並探討其可見光吸收光譜及螢光放光光譜等光學性質，(4)利用製程步驟的操控，首次在矽基材上合成出自組裝p型氧化銦奈米線陣列，再利用奈米線陣列結構製做出場效應電晶體，量測電學性質，同時利用離子佈植法植入不同濃度氮離子加以調控奈米線之電阻率。

關鍵字

矽 ； 矽化物 ； 氧化銦

並列摘要

ABSTRACT

PART Ⅰ Si and Silicide Nanostructures
The mechanical properties of single Si nanowire has been investigated. These nanowires showed anomalous flexibility and toughness. The strain of the nanowires was calculated and simulated (>1.5%) to be much higher than the bulk value (<0.2%). Under large deformation of the buckling effect, the spring constant was much lower (~10-4) due to the geometry but the elastic modulus of the nanowire would maintain the same value of the bulk elastic modulus. This result clarified the influence of the nano-sized effect. Meanwhile, the heat endurance and electric property of the cobalt silicide nanocable has been measured. The heat endurance of the nanocable was raised up to 900 ℃, which is 500 ℃ more than that of the nanowire. The nanocable shows that the resistivity could be better than the thin film due to the high quality crystallinity and structure.
By Si wafer bonding, Si bicrystal can be formed with different kinds of dislocation arrays. One-dimensional dislocation array can be formed by (001)Si and (110), (111)Si wafer bonding. The dislocation array would confine the shape of the nickel nanosilicide when the distance of the dislocation array is relatively short (<10 nm). In the in situ observation in ultrahigh vacuum transmission electron microscope, the stepwise growth of the silicide nanorod was observed for the first time. The presence of the dislocation line (d~3.1nm) would confine the shape of the silicide nanorod.

PART Ⅱ In2O3 Nanostructures
Two kinds of the In2O3 nanostructures were synthesized for the first time. The position control of the growth of the nanorings was conducted in conjunction with polystyrene spheres. The absorption and emission peak of the nanorings were at 600 and 620 nm in wavelength. The growth of In2O3 nanowires with different zinc doping levels in the vacuum furnace by a vapor transport and condensation method has been conducted. The ultraviolet peak is attributed to the transition of electrons from oxygen vacancy energy level near the electron band edge to the valence band. The green light emission, on the other hand, is ascribed to the radaitve emission between oxygen vacancy and zinc impurity energy levels. Similar tuning by other impurities can be expected and will be beneficial for possible optoelectronic applications. In addition, laterally self-aligned In2O3 nanowire and nanorod arrays on Si substrate were synthesized for the first time. The orientation relationships between the nanowires and the substrates are In2O3(111)[2 ] || Si(001)[110]. The In2O3 nanowire was found to be p-type semiconductor and the electric conductivity of the nanowire was tuned by nitrogen doping by ion implantation.

參考文獻

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