標題: Beta矽化鐵塊材的合成及電性量測
Synthesis of bulk β-FeSi2 and its electrical measurement
作者: 王傑彥
Je-Jen Wang
張振雄
王興宗
Chen-Shiung Chang
S. C. Wang
光電工程學系
關鍵字: 矽化鐵;熱電轉換效率;FeSi2;Thermoelectric power
公開日期: 1998
摘要: β-FeSi2是相當吸引人的材料,具高熱電轉換效率,對可見光有高的吸收係數,容易與Si的製程整合,文獻上顯示其具有熱能隙(Thermal energy gap)約在0.87eV至0.95eV之間。在本論文中我們嘗試以不同的合成方法及不同的退火條件,合成β-FeSi2。發現在800℃的退火溫度,1000小時的退火時間,以及快速冷卻的方法,會有較佳的熱電轉換效率,而且在材料中摻雜銅,在熱電轉換效率的表現上也得到不錯的結果。猜測較高的熱電轉換效率是因為ε相與α相及Si在退火後或摻雜銅時,易轉換成β-FeSi2。我們也以粉末X-RAY繞射、拉曼散射量測、SEM與EPMA來分析材料的合成品質、組成與成分。此外,以變溫電阻率的量測去觀察β-FeSi2的導電特性,得到它的熱能隙約在0.82eV至0.88eV之間;在低溫區(100K至200K),電阻率和溫度間的關係符合Mott定律,暗示材料內含有高濃度雜質和缺陷。
β-FeSi2 is an attractive material because of its high thermoelectric power,high absorption coefficient of visible light,and the integrating on silicon substrate﹒The thermal energy gap ofβ-FeSi2 has been reported 0.87eV-0.95eV in some literatures[1][2]﹒In this research,we synthesized and annealed theβ-FeSi2 in some different conditions﹒Theβ-FeSi2 was observed higher thermoelectric power in the condition that the syntheticβ-FeSi2 was quenched,and then annealed at 800℃,sustained 1000 hours﹒We also found that the copper-dopedβ-FeSi2 performed higher thermoelectric power﹒The higher thermoelectric power could be becauseβ-FeSi2 was formed fast fromε-FeSi and α-Fe2Si5 after annealing or doping copper﹒Structural characterizations were made by X-ray diffraction,Raman scattering,scanning electron microscopy and electron probe microanalyzer﹒Further more,ther result of measurement of resistivity as a function of reciprocal temperature is shown with a thermal energy gap 0.82eV-0.88eV﹒At low temperature(100K-200K),the temperature dependence of the resistivity matched well with Mott's exp(To/T)^(1/4)law,indicating high impurity and defect in our materials﹒
URI: http://140.113.39.130/cdrfb3/record/nctu/#NT870614023
http://hdl.handle.net/11536/65039
Appears in Collections:Thesis