本論文的工作是利用X光吸收光譜近邊緣結構研究一系列摻雜Sb及Se的Bi2Te3粉末，以探討其摻雜與熱電性質量測的關係。從熱電性質量測結果看到，在摻雜Sb的系列中，改變其摻雜濃度會出現不同型式的傳輸載子。經由X光吸收譜近邊緣結構中我們看到摻雜Sb系列的樣品在不同傳輸載子型式下的載子數量皆為增加，而在摻雜Se系列樣品中載子數量卻為減少。此外我們將吸收譜與電阻率量測的結果比對後，發現Sb摻雜使電阻率隨載子濃度的增加而增加，而Se摻雜使電阻率隨著載子濃度減少而增加，得到了不論在Bi-site或Te-Site上的摻雜都會使得載子移動率減少以致於電阻率增加的結果。 In order to study the correlation between doping effect and the thermoelectric property, we have performed x-ray absorption near-edge structure (XANES) study on a series of thermoelectric materials of Bi2-xSbxTe3(x=0,0.5, 1.0 and 1.5) and Bi2Te2.7Se0.3 powders. In the Sb-doped systems, according to the result of the thermopower measurement we found different types of carrier appeared when doping different concentration of Sb. The XANES spectra show that in both p-type and n-type samples, carriers are increased in Sb-doped systems, and decreased in Se-doped systems. After comparing the result of XANES and resistivity measurement, it shows that the resistivity is positively related to the concentration of the carriers when doping Sb; however, the resistivity is negatively related to the concentration of the carriers when doping Se. As a result, any substitution in either Bi-site or Te-site will likely have negative effects on the carrier mobilities.