本研究採用溶膠凝膠法(sol-gel method)，以NH4VO3和Ti(OC3H7)4為前驅物(precursor)合成V1-xTixO2，目的是為了提升整體的化學均勻性，並著重於探討VO2-TiO2的相圖。其中，在VO2-TiO2系統中，在臨界溫度以下會發生可逆的spinodal相分離，而高於此溫度則會轉變為均勻的固溶體。藉由分析X光繞射圖，計算單相V1-xTixO2的晶格常數和Ti4+摻雜量的關係式，並由V0.7Ti0.3O2在不同溫度熱處理後發生spinodal相分離的結果，計算出相圖中spinodal line的臨界溫度為802K、臨界成分為35 mol % Ti。透過穿透式電子顯微鏡觀測顯微結構，結果顯示在發生spinodal相分離的成分中，有V-rich相和Ti-rich相組成的層狀結構，且其波長介於20-48 nm；而在發生成核成長的成分中，則會在基材中生成圓棒狀的不連續相。在電性表現方面，若發生spinodal相分離，在溫度介於318-341K有半導體急遽轉變成導體的現象，且隨著摻雜的Ti4+含量增多，其相變化溫度有降低的趨勢。

Spinodal decomposition with a reversible transformation between single and multiple phases takes place below a critical temperature in the system of vanadium-titanium oxide. To enhance chemical homogeneity, a sol-gel method using a mixture of ammonium vanadate and titanium isopropoxide is applied. Changes in the lattice parameter of single-phase state are analyzed by X-ray diffraction. The spinodal line, determined by annealing V0.7Ti0.3O2 at different temperatures in argon, has a critical temperature of 802K at a composition of 35 mol % Ti. Transmission electron micrographs reveal the spinodally decomposed samples have the lamella structures consisted of V-rich and Ti-rich layers with a wavelength of 20-48 nm, and the samples with nucleation & growth form the rod-like phase within the matrix. The metal-insulator transition takes place at reduced temperatures of 318-341K and a decrease in the metal-insulator transition temperature is observed with increasing amount of Ti4+ for the spinodally decomposed samples.

摘要 I
Abstract II
目錄 III
圖目錄 IV
第一章　前言 1
第二章　實驗方法 4
2.1 V1-xTixO2粉體合成及試片製備 4
2.1.1 V1-xTixO2前驅物合成 4
2.1.2 試片製備 4
2.2 性質量測 5
2.2.1 X-ray繞射分析 5
2.2.2 顯微結構觀察 5
2.2.3 電性量測 5
2.2.4 吸放熱量測 6
第三章　結果與討論 7
3.1 VO2-TiO2相圖 7
3.1.1 單位晶格體積和成分的關係式V(x) 7
3.1.2 spinodal相分離之V-rich相和Ti-rich相成分點 8
3.1.3 相圖的spinodal和binodal lines 9
3.2 V1-xTixO2顯微結構 10
3.2.1 單相區 10
3.2.2 成核成長 10
3.2.3 spinodal相分離 11
3.2.4 V1-xTixO2相圖修正 13
3.3 V1-xTixO2相變化溫度 13
3.4 V1-xTixO2電性表現結果 14
第四章　結論 17
第五章　參考文獻 18

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