本論文是以X光吸收光譜研究CoSi合金，探討Al與Ge摻雜量的差異與熱電性質間的關係。在Al摻雜的系列中做了Co L2,3-edge和Co K-edge，在Ge摻雜的系列中做了Co L2,3-edge、Co K-edge及Ge K-edge。在CoSi1-xAlx系列樣品摻雜量小於0.05時，電洞被帶進了系統中，但不是在Co 3d軌域，而在摻雜量大於0.05時，電洞持續的增加，並且反應在Co 3d軌域上。在CoSi1-xGex系列樣品中可以知道Co 3d-Ge 4p之間有電子遷移的現象，影響了費米能階附近的能態密度，而造成Seebeck係數的改變。Ge K-edge吸收譜圖的主峰能量沒有明顯的位移，由此可以判斷CoSi1-xGex系列Ge的價數沒有隨著Ge摻雜量不同而顯著改變。根據Co K-edge的吸收光譜中發現，Al及Ge的摻雜並不會使吸收主峰的能量位置有明顯改變，顯示Co的價數皆不隨摻雜而改變。 We report the effects of Al and Ge partial substitution for Si on the thermoelectric materials of CoSi alloys CoSi1-xAlx (0 ≤ x ≤ 0.12) and CoSi1-xGex (0 ≤ x ≤ 0.15). We have performed X-ray absorption near edge structure (XANES) study the correlations between electronic structure and the thermoelectric properties. In the CoSi with different Al substitution, the hole was carried into the system gradually. Al substitution for Si (x ≤ 0.05), the hole was not carried into the Co 3d states. Upon further Al substitution for Si (x ≥ 0.05), the hole was carried into the Co 3d states. In the CoSi with different Ge substitution, the charge transfer between Co 3d and Ge 4p affect density of states at Fermi level, which makes Seebeck coefficients(S) change. Co K-edge of XANES shows that increased Al and Ge concentration do not affect the absorption intensity. We also observed that the valence of Co does not change with the doping.
