摘要 此研究是利用乾壓成型餅狀的鈦酸鍶(SrTiO3)塊材作為研究材料，在一般大氣壓下高溫燒結，此過程著重於鈦酸鍶受氧分壓與添加物氧化鈮(Nb2O5)的影響，觀察在微結構與缺陷化學上的差異；利用XRD繞射光譜、CL光譜、掃瞄式與穿透式電子顯微鏡作為研究工具，分析不同氧分壓與不同添加濃度下鈦酸鍶的微結構與缺陷化學反應。添加了Nb2O5之後的鈦酸鍶，預期部份的鈦離子(Ti+4)在晶體中的位置會被鈮離子(Nb+5)所取代，而使晶體產生缺陷及扭曲。此外，需由EDS能譜分析產生的第2相組成，及最後希望由XRD來驗證鈮是否使晶體產生了扭曲及由CL來驗證缺陷的種類並利用CL光譜來觀察添加前後鈦酸鍶能階的改變，然而除了缺陷化學的分析之外，在微結構上添加了鈮的試片其晶粒(約10μm)比未添加的試片(約0.5~1μm)大許多，前人(Fujimoto M.; Kyung J.Yoon[14][17])認為是因為化學位能與組成濃度不同導致晶粒成長，對於此依然需進一步由實驗上得到驗證。對於添加了鈮的試片其晶粒成長的原因，前人C.J. Peng[25]認為是因為存在著液相的原因，但在本實驗中並無觀察到任何液相的存在卻依然有晶粒成長，C.J. Peng[25]同時也認為在添加鈮所產生的補償缺陷為金屬空缺，但此點有待考證。

Abstract SrTiO3 is cubic at room temperature, and retains cubic until the phase transition to tetragonal at 105K (-168oC). It is a wide-band-gap semiconductor having an energy gap Eg ≈ 3.0 eV, when its semiconductivity is greatly improved by doping with donor oxides, e.g.Nb2O5 or heat treatment in low oxygen partial pressures (Po2). Donor oxides in solid solution with SrTiO3 forming substitutional defects create electron or cation vacancies as the principal charge compensation defect. In-gap levels are also modified by the oxygen partial pressure (Po2) adopted in sintering, which generates oxygen vacancies in order to maintain the overall charge neutrality in the ceramic. In this research, donor-doping and Po2 used in sintering are investigated for the in-gap-level modification using the cathodoluminescence (CL) spectrometry equipped with a scanning electron microscope (SEM). Other analytical techniques, e.g. transmission electron microscopy (TEM) will be used for characterizing the defect structure. Preliminary results suggest that the in-gap levels are registered at 3.10 eV and 2.69 eV, representing the intrinsic Eg and a donor-level created by oxygen vacancies, respectively.

目錄
Abstract 3
摘要 4
圖目錄 7
表目錄 12
第一章 前言 13
第二章 鈦酸鍶的結構、缺陷化學與文獻回顧 14
2-1鈦酸鍶的結構與特性 14
2-2 平衡相圖 16
2-3 鈦酸鍶的缺陷化學 17
2-3.1氧分壓對缺陷濃度的影響: 19
2-3.2 Sr/Ti(粉體組成)對於缺陷濃度的影響: 22
2-3.3雜質(Nb2O5)對於缺陷濃度的影響: 23
2-3.4溫度對於缺陷濃度的影響: 24
2-4 文獻回顧 25
第三章 實驗步驟 28
3-1起始粉末 28
3-2 試片製程 28
3-2.1大氣下燒結-未添加Nb試片 29
3-2.2大氣下燒結-已添加Nb試片 30
3-2.3低氧下燒結-未添加Nb試片 30
3-2.4低氧下燒結-已添加Nb試片 31
3-2.5 導電度與燒結密度量測 33
3-3觀察設備與前處理： 34
3-3.1 x-ray繞射分析儀： 34
3-3.2光學顯微鏡(OM)與掃描電子顯微鏡(SEM)： 34
3-3.3穿透式電子顯微鏡(TEM)： 35
3-3.4 Cathodoluminsecense (CL) 37
第四章 實驗結果 38

4-1 SrTiO3 X-ray研究 38
4-2 SrTiO3晶格常數計算 45
4-3 SrTiO3 密度量測 49
4-4導電度的量測 50
4-5 SrTiO3 表面微結構分析 53
4-5.1 大氣下燒結doped-Nb2O5 SrTiO3 微結構分析 53
4-5.2 大氣下燒結undoped SrTiO3 微結構分析 59
4-5.3低氧分壓下燒結doped Nb2O5 SrTiO3 微結構分析 62
4-5.4低氧分壓下燒結undoped SrTiO3 微結構分析 66
4-6 CL光譜量測 69
4-6.1常溫下CL光譜量測(大氣燒結) 69
4-6.2常溫下CL光譜量測(低氧燒結) 73
4-7 TEM 觀察 76
大氣下燒結Nb2O5-doped SrTiO3 TEM分析 77
低氧分壓下燒結Nb2O5-doped SrTiO3 TEM分析 86
第五章 討論 92
5-1比較在大氣下燒結 doped 與un-doped試片 92
5-2比較在低氧下燒結 doped 與undoped試片 94
5-3 比較相同組成，不同燒結環境下的微結構差異 95
5-4 CL光譜比較 96
5-5 由缺陷反應所產生的TiO2 97
5-6 Charge Transfer Vibronic Exvtion(24eV) 97
第六章 結論 98
第七章 未來工作 100
附錄1 XRD Data base 101
附錄2 Kikuchi Map (SrTiO3) 102
附錄3 AEM JEOL3010 105
參考文獻 106

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