Energy-level alignment at the Alq3/Fe3O4(001) interface
Energy-level alignment at the Alq3/Fe3O4(001) interface
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DOI：
10.1063/1.3677768
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发表时间：
2012-03
影响因子：
3.2
通讯作者：
A. Pratt;L. Dunne;X. Sun;M. Kurahashi;Y. Yamauchi
中科院分区：
文献类型：
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作者：
A. Pratt;L. Dunne;X. Sun;M. Kurahashi;Y. Yamauchi
我们利用亚稳态去激发光谱技术研究了沉积在干净的Fe_3O_4（001）衬底上的有机半导体Al_q_3的界面电子结构。我们已经测量了低能量的二次电子截止和高能的最高占据分子轨道（HOMO）的Alq3的覆盖范围从子ML范围增加到多层形成的开始的移位。我们发现，一个界面偶极子的存在下诱导的价带电子态的均匀减少了1.2 eV的真空水平和修改的HOMO能量开始的位置低于基板费米能级1.8 eV。强烈的固有偶极矩的Alq3被建议为这些变化的起源，根据先前的研究Alq3沉积到各种基板上。
We have used the technique of metastable de-excitation spectroscopy to probe the interfacial electronic structure of the organic semiconductor (OSC) Alq3 deposited onto clean Fe3O4(001) substrates. We have measured shifts in the low-energy secondary electron cutoff and energetic onset of the highest occupied molecular orbital (HOMO) of Alq3 as the coverage increases from the sub-ML range to multilayer formation. We find that the presence of an interfacial dipole induces a uniform decrease in the valence band electronic states by 1.2 eV with respect to the vacuum level and modifies the position of the HOMO energetic onset to 1.8 eV below the substrate Fermi level. The strong intrinsic dipole moment of Alq3 is suggested as the origin for these changes in accordance with previous studies of Alq3 deposited onto various substrates.