臺灣博碩士論文加值系統

摘要
本研究成功的使用了無毒且簡易的物理氣相傳輸法(PVD),在氧化鋁基板上合成出鍺/氧化鍺核-殼奈米線異質結構，首先利用高溫熱蒸鍍法將鍺金屬蒸氣傳輸至鍍金退火後的氧化鋁基板上成長鍺奈米線，接著利用通入不同氣氛的氧環境之下，成長出具有不同厚度氧化鍺的鍺/氧化鍺核-殼奈米線的異質結構。樣品首先由掃描式電子顯微鏡與能量分散式光譜儀進行初步的材料鑑定，觀察鍺/氧化鍺為奈米線結構線徑小於80奈米，奈米線表面平滑，確認試片只存在鍺和氧元素，並無其他成分及汙染物。接著我們將試片進行XRD晶體結構鑑定，在低氧氣氛下(0%、1%、5%)主要為立方晶(cubic)結構鍺奈米線所組成，而在高氧氣氛10%，為立方晶結構鍺與六方晶(hexagonal)二氧化鍺奈米線所組成並具有良好結晶性質。接著我們使用掃描穿透式電子顯微鏡(STEM)鑑定奈米線的顯微結構及成分，確認樣品隨著氧氣氛增加，殼層氧化鍺的厚度也隨之增厚，在低氧氣氛(0%、1%、5%)下所成長的試片為鍺/氧化鍺(GeOx)奈米線結構，及在高氧氣氛10%所成長的樣品為鍺/二氧化鍺/氧化鍺多層奈米線核-殼異質結構。接著我們利用光電子光譜術確認了樣品表面化學鍵結態。微拉曼光譜，顯示樣品鍺的拉曼訊號隨著樣品尺度的改變而有紅移(Red Shift)的現象，推論是因為樣品的小線徑及聲子侷限效應所導致。在光激發螢光光譜中，得知鍺/氧化鍺奈米線結構具有波長約525nm藍綠可見光波段的PL發光性質，推測是由於材料中的氧空缺、鍺-氧空缺缺陷躍遷所貢獻， 因此鍺/二氧化鍺奈米線異質結構具有半導體發光元件的發展潛力。

Abstract
The Ge/Ge/GeOx nanowire core-shell nanowire heterostructures were synthesiz-ed on the sapphire substrates by using a non-toxic physical vapor deposition method. First, Ge vapor were transported onto the Au coated sapphire substrates to grow Ge nanowires. By controlling the ambient oxygen (0%, 1%, 5%, and 10%) during growth, Ge/GeO2/GeOx nanowire heterostructures with different shell thickness can be obtained. The field-emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDS) were used to characterize samples. The sample consi-sts of nanowires with smooth surface and their diameters were less than 80 nm. EDS results shows only Ge and O were detected on samples, confirming the high purity of sample. The X-ray diffraction results confirm the crystal structures are cubic Ge and hexagonal GeO2 with high crystallinity. The scanning transmission electron micros-cope (STEM) was used to further characterize nanowire heterostructures. The results reveals that with increasing oxygen ambient, the thickness of oxide layer increases. For samples obtained under low oxygen ambient (0%, 1%, and 5%) were Ge/GeOx core-shell nanowire heterostructures. Sample grown under high oxygen ambient (10%) was Ge/GeO2/GeOx core-shell nanowire heterostructures. Their surface valence states were further confirmed by X-ray photoelectron spectroscopy (XPS). Macro-Raman spectroscopy indicates a red shift behavior due to size effect and phonon confinement. Photoluminescence (PL) results shows Ge/GeOx core-shell nanowire heterostructures are with strong blue-green emission due to various defect transitions such as oxygen vacancy and germanium-oxygen vacancy pairs.

目錄
摘要 I
Abstract III
目錄 IV
圖目錄 V
表目錄 X
第一章 緒論 1
1.1 前言 1
1.2 研究目標 1
第二章 文獻回顧 3
2.1二氧化鍺基本性質與應用 3
2.1.1熱蒸鍍法 3
2.1.2化學氣相傳輸法(CVD) 3
2.1.3碳還原法 3
2.2鍺基本性質與合成 5
2.2.1鍺性質與應用 5
2.2.2合成一維奈米結構鍺 5
2.3二氧化鍺異質結構 6
2.3.1異質結構 6
2.3.2鍺與二氧化鍺奈米異質結構合成方法 6
第三章 實驗材料及步驟 15
3.1 實驗流程與設計 15
3.2 實驗儀器與材料 15
3.2.1合成使用儀器與基板 15
3.2.2清潔溶劑 15
3.2.3奈米結構成長源 15
3.3 實驗步驟與設置 16
3.3.1基板成長前處理 16
3.3.2 鍍金氧化鋁基板成長一維鍺/氧化鍺奈米線核-殼異質結構 16
3.4 分析儀器 17
3.4.1 場發射掃描式電子顯微鏡(FE-SEM) 17
3.4.2 能量分散式光譜儀(EDS) 18
3.4.3 顯微拉曼光譜儀(Macro-Raman) 18
3.4.4 X光繞射分析儀(XRD) 19
3.4.5 光致激發光譜儀(PL) 19
3.4.6 穿透式電子顯微鏡(TEM) 19
3.4.7 X光電子能譜儀(XPS) 20
第四章 實驗結果與討論 25
4.1成長鍺/氧化鍺奈米線核-殼異質結構 25
4.1.1表面形貌與元素分析 25
4.1.2 X光繞射晶體結構分析 27
4.1.3 TEM顯微結構分析與鑑定 28
4.1.4 TEM顯微結構元素分布分析 30
4.1.5異質結構之成長機制 31
4.1.6小結論 33
4.2不同氧氣氣氛下之光學性質與表面元素分析 34
4.2.1 X光光電子能譜表面元素分析 34
4.2.2顯微拉曼光譜分析 36
4.2.3光致螢光光譜分析 38
第五章 結論 65
第六章 參考文獻 67


圖目錄

圖2.1二氧化鍺(GeO2)相圖[5] 8
圖2.2 Rutile二氧化鍺(GeO2)晶體結構圖 8
圖2.3 α-quartz二氧化鍺(GeO2)晶體結構圖 9
圖2.4 二氧化鍺奈米線(GeO2)成長機制圖[11] 9
圖2.5二氧化鍺(GeO2)光致激發光譜圖[12] 10
圖2.6 鍺立方晶(cubic)晶體結構 10
圖2.7 鍺奈米線高解析穿透式電子顯微鏡影像圖[16] 11
圖2.8 鍺奈米線陣列應用於鋰離子電池示意圖[17] 11
圖2.9鍺奈米線應用於半導體元件圖[18] 12
圖2.10 鍺奈米線VLS-VSS成長機制圖[20] 12
圖2.11 半導體異質結構能帶圖[21] 13
圖2.12 二氧化鍺/鍺異質結構能帶圖[22] 13
圖2.13 鍺/二氧化鍺 核-殼異質結構之TEM高解析影像圖[27] 14
圖3.1 鍍金機(JEOL JFC-1600 ) 21
圖3.2 水平式高溫管型爐 21
圖3.3 場發射電子顯微鏡(JSM-7000F) 22
圖3.4 微拉曼光譜儀(Renishow-1000B) 22
圖3.5 高功率低角度薄膜X光繞射儀（Rigaku D/Max-2500V X-ray Diffractometer） 23
圖3.6 光致激發光光譜儀(PL) 23
圖3.7 熱燈絲穿透式電子顯微鏡(AEM, JEOL JEM-3010) 24
圖3.8 場發射式穿透式電子顯微鏡(Philips Tecnai F20 G2 FEI-TEM) 24
圖3.9 X光電子能譜儀(XPS) 24
圖4.1 氧氣氛0%，不同成長溫度樣品奈米線表面形貌與生成密度分析之FE-SEM影像圖(a)500oC (b) 600oC (c) 700oC 39
圖4.2 氧氣氛1%，不同成長溫度樣品奈米線表面形貌與生成密度分析之FE-SEM影像圖(a)500oC (b) 600oC (c) 700oC 40
圖4.3 氧氣氛5%，不同成長溫度FE-SEM樣品奈米線表面形貌與生成密度分析之FE-SEM影像圖(a)500oC (b)600oC (c)700oC 41
圖4.4 氧氣氛10%，不同成長溫度樣品奈米線表面形貌與生成密度分析之FE-SEM影像圖(a)500oC (b)600oC (c)700oC 42
圖4.5 氧氣氛10%，不同成長溫度樣品奈米線表面形貌與生成密度分析之FE-SEM高倍率影像圖(a)500oC (b) 600oC (c)700oC 43
圖4.6成長溫度600 oC不同氧氣氛樣品進行元素定性與半定量分析之EDS圖(a)1%氧氣氛、(b)5%氧氣氛、(c) 10%氧氣氛 44
圖4.7 氧氣氛0%，500 oC -700 oC成長溫度樣品具有鍺立方晶繞射峰之XRD圖 45
圖4.8 氧氣氛1%，500 oC -700 oC成長溫度樣品具有鍺立方晶繞射峰之XRD圖 45
圖4.9 氧氣氛5%，500 oC -700 oC成長溫度樣品具有鍺立方晶繞射峰之XRD圖 46
圖4.10 氧氣氛10%，500 oC -700 oC成長溫度樣品具有鍺立方晶與二氧化鍺六方晶繞射峰之XRD圖 46
圖4.11 鍺粉與二氧化鍺奈米線樣品之XRD繞射圖 47
圖4.12 氧氣氛5%，成長溫度600oC樣品圈選奈米線紅框處進行鑑定殼層鍺之TEM選區電子繞射圖(SAED) 47
圖4.13 氧氣氛100%，成長溫度950oC二氧化鍺奈米線於紅色框處進行結構鑑定之選區電子繞射圖(SAED) 48
圖4.14 氧氣氛1%，成長溫度600oC樣品具有核-殼層不同材料影像對比之TEM-HR影像圖 48
圖4.15(a)、(b) 氧氣氛5%，成長溫度600oC樣品具有核-殼層不同材料影像對比之TEM-HR影像圖 49
圖4.16(a)-(c) 氧氣氛10%，成長溫度600oC樣品具有核-殼層不同材料影像對比之TEM-HR影像圖 50
圖4.17(a)-(b) 氧氣氛10%，成長溫度600oC樣品奈米核殼異質結構對於紅色框選處進行場發射穿透式電子顯微鏡高解析影像分析，紅色框選處具有核-殼層不同材料影像對比之TEM影像與高解析影像圖 51
圖4.18(a)-(b) 奈米線核-殼層介面紅色圈選區域進行高解析影像分析，具有多層材料結構組成與良好結晶性之TEM超高解析影像圖 52
圖4.19(a)-(c) 氧氣氛10%，成長溫度600oC樣品具有奈米線上鍺與氧訊號分布資訊之TEM mapping圖 53
圖4.20(a)-(b) 氧氣氛10%，成長溫度600oC樣品具有奈米線核-殼層鍺與氧元素分布資訊之TEM line-scan圖 54
圖4.21為奈米線異質結構成長機制驗證之無鍍金基板進行成長，(a)、(b)為溫度500oC、(c)、(d)為700oC，氧氣氛10%樣品之FE-SEM影像圖 55
圖4.22氧氣氛10%，成長溫度700oC未鍍金樣品進行元素定性分析與半定量分析之EDS圖 56
圖4.23金觸媒存在於樣品奈米線頂端處之TEM高解析影像分析圖 57
圖4.24 Au-Ge二元相圖 58
圖4.25在不同氧氣氛(0-10%)成長出具有不同奈米線異質結構組成之機制圖 59
圖4.26 不同氧氣氛(0%-10%)，成長溫度600oC樣品之XPS全譜圖 60
圖4.27 不同氧氣氛(0%-10%)，成長溫度600oC樣品之O1s圖 60
圖4.28 不同氧氣氛(0%-10%)，成長溫度600oC樣品之Ge3d分峰圖 61
圖4.29 Ge3d軌域之二氧化鍺、氧化鍺、鍺XPS訊號與氧氣氛變化圖 61
圖4.30(a)不同氧氣氛(0%-10%)，成長溫度600oC樣品之微拉曼光譜圖 62
圖4.30(b)樣品氧氣氛增加拉曼會具有往低波數偏移特性之微拉曼區域圖 62
圖4.31不同氧氣氛(0%-10%)，成長溫度600oC鍺/二氧化鍺異質結構樣品具有二氧化鍺PL放光特性之PL放光圖 63
圖4.32不同氧氣氛(0%-10%)，成長溫度700oC鍺/二氧化鍺異質結構樣品具有二氧化鍺PL放光特性之PL放光圖樣品之PL放光圖 63
表目錄
表4.1不同氧氣氛下樣品微拉曼峰值位移與半高寬表…...64

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