X光吸收光譜對鋁掺雜之碲化鋅(ZnTe)電子與原子結構的研究

Electronic and structural properties of Al-doped ZnTe studied by x-ray absorption spectroscopy

吳偉銘(Wei-Ming Wu)

指導教授 ： 張經霖

淡江大學/理學院/物理學系碩士班/碩士(2014年)

https://doi.org/10.6846/TKU.2014.00829

摘要

此論文主要是對碲化鋅燒製溫度變化和摻雜鋁變化之X光近邊緣結構 (X-ray absorption near edge structure，XANES)和延伸X光吸收精細結構 (X-ray absorption fine structure，EXAFS)還有電阻率(Resistivity)和熱電力(Seebeck)做數據分析。XANES的結果指出隨著燒製溫度上升，Zn的K-edge主吸收峰吸收強度減弱而衛星峰吸收強度增強，Te的L3-edge主吸收峰吸收強度沒有明顯變化，肩峰吸收強度減弱，此結果顯示Zn的5d軌域與Zn的4s軌域有混成的現象且隨著燒製溫度上升而增強，顯示Te 5p有電子轉移Zn 4s與Zn 4p現象。在Zn K-edge EXAFS的結果顯示隨燒製溫度上升的第一配位層的主峰強度減少，表示原子排序亂度變大且有雜相。在摻雜鋁變化中，在摻了Al0.05後，Zn 4s有電子轉移Te 5p現象，Te 5p未佔據態隨摻Al0.05而空軌域變多，顯示其電洞載子增加，電阻率下降和其有關。

關鍵字

碲化鋅 ； 碲化鋅摻雜鋁 ； X光近邊緣結構 ； 延伸X光吸收精細結構

並列摘要

This thesis studies zinc telluride doped with aluminum and fired at different temperatures. X-ray absorption near edge structure, (XANES) and X-ray absorption fine structure, (EXAFS). Our results are compared with the thermal power (Seebeck) and resistivity measruements. The results indicated that as the firing temperature increases Zn K-edge XANES main absorption peak intensity decreased and the satellite peak intensity enhances. Te L3-edge main absorption peak intensity does not change significantly and the intensity of the shoulder shows that the 5d orbitals of Zn and Zn 4s orbitals have significant hybridization. As the firing temperature rises a Te 5p to Zn 4s and Zn 4p. electron transfer are observed. Zn K-edge EXAFS results show that the first shell peak intensity decreased with the firing temperature, which indicates the atomic ordering becomes larger. In sample doped with 5% Al , there is a Zn 4s Te 5p to Te 5p electron transfer. Unoccupied states and empty orbitals increases, which indicates the hole carriers increases in Al doped sample. The result in consistence with transport measurements.

並列關鍵字

XANES ； EXAFS ； ZnTe ； ZnTe:Al

參考文獻

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