矽團簇取代基的部分取代效應對能隙影響之理論計算研究

Theoretical investigation of the partial substituent effect of the energy gap of silicon clusters

簡郁璋(Yu-Chang Chien)

指導教授 ： 王伯昌

淡江大學/理學院/化學學系碩士班/碩士(2008年)

https://doi.org/10.6846/TKU.2008.00454

摘要

使用SIESTA搭配B3LYP的方法來研究矽團簇取代基效應對其光學性質的影響。本篇論文選擇以Si35的Td點群矽團簇來進行計算。對矽團簇的全取代方面增加了氟元素對矽團簇的全取代計算，並與之前不同取代基對矽團簇全取代的結果比較。而在部分取代上我們選用五個較單純的取代基分別為-CH3、-CH=CH2、-OH、-NH2與-SH作為討論的對象，來計算部分取代後矽團簇的HOMO、LUMO與能隙值。計算結果得到具有強陰電性的F與OH對矽團簇的全取代上，會得到較低的能隙值。而在五種不同取代基對矽團簇的部分取代上，對HOMO的比較中，隨著NH2取代基的增加上升幅度最高，而SH的上升幅度是最小的；在LUMO的比較中，OH與SH會隨著取代基增加而下降；能隙的比較中可以看到OH隨著取代基增加有最低的能隙值。

關鍵字

矽團簇 ； 部分取代 ； 能隙 ； 理論計算

並列摘要

For the investigation of the optical properties of Si nanoclusters as a function of surface passivation, we carried out a B3LYP/SIESTA calculation in the Si35 core clusters with different full passivated and partial passivated effect for the Td symmetry. We add F-terminations calculation for full passivated in order to compare the calculation results with data which we did in the past. In the part of partial passivated, we choice five sample substituents including CH3-, CH=CH2-, OH-, NH2- and SH- terminations and calculate their HOMO, LUMO and energy gap further. The full passivated calculated optical properties of F and OH passivation in Si35 nanoclusters [Si35F36 and Si35(OH)36], the energy gap is lower then another substituent. In the partial passivated calculated result, the energy gap decreases with increasing the OH substituent and makes the trend become lowest with other substituents.

並列關鍵字

Silicon clusters ； computational chemistry ； partial substituent effect ； energy gap ； SIESTA

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