Thickness dependence of the LUMO position for phthalocyanines on hydrogen passivated silicon (111)
Thickness dependence of the LUMO position for phthalocyanines on hydrogen passivated silicon (111)
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DOI：
10.1016/j.apsusc.2004.05.065
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发表时间：
2004-07-15
影响因子：
6.7
通讯作者：
Zahn, DRT
中科院分区：
文献类型：
--
作者：
Gorgoi, M;Michaelis, W;Zahn, DRT
利用反向光电子能谱（IPES）研究了氢钝化Si（111）衬底上氟化和非氟化库珀酞菁层的未占电子态密度。对于非氟化库珀酞菁（CuPc）的最低未占分子轨道（LUMO）被发现逐渐向费米能级随着膜厚度的增加。位移量为400毫电子伏，并出现在一个单层和10纳米之间的膜厚度。这一发现补充了以前的结果，使用紫外光电子能谱的最高占据分子轨道（HOMO）被发现作为膜厚度的函数移动。氟化库珀酞菁（F16CUPc）表现出相反的行为，即LUMO和费米能级之间的距离增加了1.2eV。(C)2004 Elsevier B.V.保留所有权利。
Inverse photoemission spectroscopy (IPES) was employed to study the density of unoccupied electronic states of fluorinated and non-fluorinated cooper phthalocyanine layers deposited onto hydrogen passivated Si(111) substrates. For the nonfluorinated cooper phthalocyanine (CuPc) the lowest unoccupied molecular orbital (LUMO) is found to shift gradually towards the Fermi level with increasing film thickness. The shift amounts to 400 meV and appears for film thicknesses between one monolayer and 10 nm. This finding complements previous results obtained using ultraviolet photoemission spectroscopy where the highest occupied molecular orbital (HOMO) was found to shift as a function of film thickness. Fluorinated cooper phthalocyanine (F16CUPc) shows the opposite behaviour, that is the distance between LUMO and Fermi level is increasing by 1.2 eV. (C) 2004 Elsevier B.V. All rights reserved.