Local heating method for growth of aligned carbon nanotubes at low ambient temperature

We use a highly localised resistive heating technique to grow vertically aligned multiwalled nanotube films and aligned single-walled nanotubes on substrates with an average temperature of less than 100°C. The temperature at the catalyst can easily be as high as 1000 °C but an extremely high temperature gradient ensures that the surrounding chip is held at much lower temperatures, even as close as 1μm away from the local heater. We demonstrate the influence of temperature on the height of multi-walled nanotube films, illustrate the feasibility of sequential growth of single-walled nanotubes by switching between local heaters and also show that nanotubes can be grown over temperature sensitive materials such as resist polymer

Synthesis of carbon nanotube films by thermal CVD in the presence of supported catalyst particles. Part I: The silicon substrate/nanotube film interface

The interface between the silicon substrate and a carbon nanotube film grown by thermal CVD with acetylene (C2H2) and hydrogen at 750 or 900 \ub0C has been characterized by high resolution and analytical transmission electron microscopy, including electron spectroscopic imaging. Silicon (0 0 2) substrates coated with a thin (2.8 nm) iron film were heat treated in the CVD furnace at the deposition temperature in a mixture of flowing argon and hydrogen whereby nanosized particles of (Fe,Si)3O4 formed. These particles were reduced to catalytic iron silicides with the α–(Fe, Si), α2–Fe2Si and α1–Fe2Si structures during CVD at 900 \ub0C, and multi-wall carbon nanotubes grew from supported particles via a base-growth mechanism. A limited number of intermediate iron carbides, hexagonal and orthorhombic Fe7C3, were also present on the substrate surface after CVD at 900 \ub0C. The reduction of the preformed (Fe, Si)3O4 particles during thermal CVD at 750 \ub0C was accompanied by disintegration leading to the formation of a number of smaller

Synthesis of carbon nanotube films by thermal CVD in the presence of supported catalyst particles. Part I: The silicon substrate/nanotube film interface

The interface between the silicon substrate and a carbon nanotube film grown by thermal CVD with acetylene (C2H2) and hydrogen at 750 or 900 \ub0C has been characterized by high resolution and analytical transmission electron microscopy, including electron spectroscopic imaging. Silicon (0 0 2) substrates coated with a thin (2.8 nm) iron film were heat treated in the CVD furnace at the deposition temperature in a mixture of flowing argon and hydrogen whereby nanosized particles of (Fe,Si)3O4 formed. These particles were reduced to catalytic iron silicides with the α–(Fe, Si), α2–Fe2Si and α1–Fe2Si structures during CVD at 900 \ub0C, and multi-wall carbon nanotubes grew from supported particles via a base-growth mechanism. A limited number of intermediate iron carbides, hexagonal and orthorhombic Fe7C3, were also present on the substrate surface after CVD at 900 \ub0C. The reduction of the preformed (Fe, Si)3O4 particles during thermal CVD at 750 \ub0C was accompanied by disintegration leading to the formation of a number of smaller

Synthesis of carbon nanotube films by thermal CVD in the presence of supported catalyst particles. Part II: the nanotube film

Carbon nanotube films have been grown at 750° and 900 °C by thermal chemical vapor deposition (CVD) with acetylene (C2H2) and hydrogen on silicon (0 0 2) wafers supporting preformed (Fe,Si)3O4 particles. The reduction of the (Fe,Si)3O4 particles during CVD at 750 °C was accompanied by a disintegration leading to the formation of a high density of smaller (predominantly 5–15 nm) iron silicide (α1-Fe2Si) particles that catalyzed the growth of a dense and aligned multi-wall carbon nanotube film. The tubes did not contain any inclusions apart from the catalytic particles present in the bottom part of the film, and it was concluded that the nanotubes grew via a “base-growth” mechanism. CVD at 900 °C resulted in a random growth of predominantly multi-wall carbon nanotubes. The film contained an increased number of amorphous carbon, or graphite, clusters containing particles that had been carbonized, the larger ones to cementite, θ-Fe3C. Nanotubes were observed to grow from some of these clusters. Multi-wall carbon nanotube tips contained after CVD at 900 °C encapsulated θ-Fe3C, or in a few cases α- or γ-Fe, particles

[[alternative]]Effect of n2 addition in ar plasma on the development of microstructure of ultra-nanocrystalline diamond films

碩士[[abstract]]奈米微晶鑽石(UNCD)薄膜因兼具良好的物理化學性質及平坦的表面，適合於電子元件的應用，且具有負電子親和力的特性。 本實驗藉由微波電漿輔助化學氣相沈積法 ( MPECVD )成長氮氫共同摻雜成長鑽石薄膜，在不同氣氛在矽基板上成長UNCD後發現，在沉積UNCD的條件下，由於氣氛中的氮氣及氫氣的不同成長條件，使得成長鑽石膜時的微結構明顯產生變化，進而研究改變氫氣及氮氣流量對場發射性質的影響以及改變氫氣流量對鑽石晶粒大小的影響。藉由拉曼的量測、SEM、場發射的量測及可見光光譜量測等來分析，其微結構和場發射的影響。本實驗最佳數據為:當氫流量8sccm和氮流量20sccm時，有最佳的場發射特性，最低起始電場5.78 V/μm。 在不同氫氣流量時，因為氫氣會蝕刻二次再孕核點，以及選擇性蝕刻SP2鍵結，可發現晶粒大小的改變，在氫流量為零時，鑽石晶粒大小約為20-50nm，隨著氫流量增加，鑽石晶粒有變大，至於氮氣的流量的改變對鑽石晶粒沒有明顯的影響，且晶粒的大小與表面形貌對電子場發射特性有顯著的影響。[[abstract]]The ultra-nanocrystalline diamond films (UNCD) posses marvelous physical &Chemical properties and have been widely investigated. The incorporation of N2 into reaction gas has been reported to effectively increase the conductivity of the materials and enhanced the electron field properties (EFE) of these films. The characteristics of The UNCD films, however, were pronouncedly affected by their microstructure, which, in turn, was intimately correlated with the constituents in plasma. In this study, we systematically investigated the effect of the plasma, the H2/N2/Ar rate, on the characteristics, especially the EFE behavior, of the UNCD films. It is found that, while the UNCD films grown in Ar plasma contain ultra-small grain size (~5 nm), incorporation of H2 or N2 into the plasma monotonously increased the size of the grains. Moreover, it modified profoundly the morphology of the UNCD grains, from equi-axed geometry to plate-like one. The optical emission spectroscopic investigation indicated that the induction of the CH-band due to the addition of H2 and the CN-band due owing to the addition of N2 into Ar plasma is the main cause, which alters the Raman structure and microstructure of the UNCD films. How the change in the OES altered these characteristics of the UNCD films will be discussed.[[tableofcontents]]目錄 第一章 緒論 １ 1.1 簡介 １ 1.2 鑽石薄膜基本特性 １ 1.3鑽石膜成核理論 ５ 1.4 鑽石薄膜的應用 １１ 第二章 研究方法及實驗步驟 １５ 2.1 微波電漿CVD鍍鑽石薄膜 １５ 2.2 實驗方法 １７ 2.3 薄膜之特性分析 １８ 2.3.1 掃描式電子顯微鏡(SEM) １８ 2.3.2 拉曼光譜分析鑽石膜品質 １９ 2.3.3 場發射電特性之量測 ２２ 2.3.4 可見光發射光譜學(OES) ２６ 　　　2.3.5 穿透式電子顯微鏡 ..３１ 第三章 研究結果與討論 33 3.1 改變氫及氮流量之N5鑽石薄膜系列 33 3.2改變氫及氮流量之N10鑽石薄膜系列 ５０ 3.3改變氫及氮流量之N15鑽石薄膜系列 60 3.4改變氫及氮流量之N20鑽石薄膜系列 67 3.5 綜合討論 77 第四章 結論 82 參考文獻 83 圖表目錄 圖2.1.1.1 Iplas 系統………………………………………………14 圖2.1.1.2 IPLAS 系統示意圖………………………………………15 圖2.3.1 SEM系統………………………………………………………18 圖2.3.2 拉曼系統……………………………………………………19 圖2.3.3電子場發射特性量測示意圖………………………………22 圖2.3.3.1.1金屬-真空能帶示意圖未加電場………………………23 圖2.3.3.1.1金屬-真空能帶示意圖外加電場………………………23 圖2.3.4.1 OES分析……………………………………………………29 圖Table 1.Table of used Ar I and II lines……………………………..30 圖3.3.5 TEM系統………………………………………………………31 圖3.1.2.1 N5場發射特性圖…………………………………………34 圖3.1.2.2 N5_F-N plot………………………………………………34圖3.1.3 N5系列拉曼………………………………………………….36 圖3.1.4.1:為氮氣5(sccm)氫氣0(sccm) …………………………38 圖3.1.4.2:為氮氣5(sccm)氫氣3.5(sccm)…………………………38 圖3.1.4.3:為氮氣5(sccm)氫氣5(sccm)……………………………38 圖3.1.4.4:為氮氣5(sccm)氫氣10(sccm)…………………………39 圖3.1.4.5:為氮氣5(sccm)氫氣15(sccm)…………………………39 圖3.1.4.6:為氮氣5(sccm)氫氣20(sccm)…………………………39 圖3.1.5 N5系列OES…………………………………………………41 圖3.1.5.1氫氣比例與溫度(K)作圖…………………………………42 圖3.1.6.1:為氮氣5(sccm)氫氣0(sccm)……………………………44 圖3.1.6.2:為氮氣5(sccm)氫氣3.5(sccm)…………………………44 圖3.1.6.3:為氮氣5(sccm)氫氣5(sccm)……………………………44 圖3.1.6.4:為氮氣5(sccm)氫氣10(sccm)…………………………45 圖3.1.6.5:為氮氣5(sccm)氫氣15(sccm)…………………………45 圖3.1.6.6:為氮氣5(sccm)氫氣20(sccm)…………………………45 圖3.2.2.1 N10場發射特性圖………………………………………51 圖3.2.2.2 N10_F-N plot……………………………………………51 圖3.2.2.3 氫氣比例與起始電場作圖………………………………52 圖3.2.3 N10系列拉曼光譜…………………………………………53 圖3.2.4.1:為氮氣10(sccm)氫氣0(sccm)…………………………55 圖3.2.4.2:為氮氣10(sccm)氫氣3.5(sccm)………………………55 圖3.2.4.3:為氮氣10(sccm)氫氣5(sccm)…………………………55 圖3.2.4.4:為氮氣10(sccm)氫氣8(sccm)…………………………56 圖3.2.4.5:為氮氣10(sccm)氫氣10(sccm)…………………………56 圖3.2.4.6:為氮氣10(sccm)氫氣20(sccm)…………………………56 圖3.2.5 N10系列OES…………………………………………………57 圖3.3.5 氫氣比例與電漿溫度作圖…………………………………58 圖3.3.2.1 N15場發射特性圖…………………………………………61 圖3.3.2.2 N15 F-N plot………………………………………………61 圖3.3.2.3 電子場發射起始電場……………………………………62 圖3.3.3 N15系列拉曼光譜……………………………………………63 圖3.3.4.1:為氮氣15(sccm)氫氣0(sccm)…………………………65 圖3.3.4.2:為氮氣15(sccm)氫氣3.5(sccm)………………………65 圖3.3.4.3:為氮氣15(sccm)氫氣5(sccm)…………………………65 圖3.3.4.4:為氮氣15(sccm)氫氣8(sccm)…………………………66 圖3.3.4.5:為氮氣15(sccm)氫氣10(sccm)…………………………66 圖3.3.4.6:為氮氣15(sccm)氫氣20(sccm)…………………………66 圖3.4.2.1 N20場發射特性圖…………………………………………68 圖3.4.2.2 N20 F-N plot………………………………………………68 圖3.4.2 氫氣流量與起始電場作圖…………………………………69 圖3.4.3 N20系列拉曼光譜…………………………………………70 圖3.4.4.1:為氮氣20(sccm)氫氣0(sccm)…………………………72 圖3.4.4.2:為氮氣20(sccm)氫氣3.5(sccm)………………………72 圖3.4.4.3:為氮氣20(sccm)氫氣5(sccm)…………………………72 圖3.4.4.4:為氮氣20(sccm)氫氣8(sccm)…………………………73 圖3.4.4.5:為氮氣20(sccm)氫氣10(sccm)…………………………73 圖3.4.4.6:為氮氣20(sccm)氫氣20(sccm)…………………………73 圖3.4.5 N20系列OES…………………………………………………74 圖3.4.5.1 氫氣比例與溫度作圖……………………………………75 圖3.5.1 電子場發射起始電場………………………………………77 圖3.5.2 拉曼光譜分析………………………………………………78 表目錄 表1.2 CVD鑽石特性參數………………………………………………5 表1.3.3 不同種類鑽石膜與類鑽石膜之特性比較……………………8 表2.3.2 碳結構的各種拉曼特性峰…………………………………21表2.3.4.1 OES特性峰……………………………………………….28表3.1.1 鍍膜參數N5系列……………………………………………33表3.1.2 N5系列的起始電場…………………………………………35表3.1.3 拉曼I(D)/I(G)……………………………………………37表3.1.5 N5系列電漿溫度……………………………………………43表3.1.6 N5系列ICN/IC2………………………………………………43表3.2.1 N10系列鍍膜參數……………………………………………50 表3.2.2 N10系列起始電場……………………………………………52表3.2.3 N10:I(D)/I(G)………………………………………………54表3.2.5 N10系列電漿溫度……………………………………………58 表3.2.5.1 N10系列ICN/IC2…………………………………………59 表3.3.1為N15系列鍍膜參數………………………………60 表3.3.2.1起始電場與氫氣流量……………………………………62 表3.3.3 N15 I(D)/I(G)………………………………………………64 表3.3.1 N20系列鍍膜參數……………………………………………67 表3.4.2 N20系列起始電場……………………………………………69 表3.4.3 N20 ID/IG……………………………………………………71 表3.3.5 N20電漿溫度…………………………………………………75 表3.4.5.2 ICN/IC2……………………………………………………76 表3.5.2 不添加氫氣I(D)/I(G)……………………………………79[[note]]學號: 696210565, 學年度: 9