Energy-level alignment at the Alq 3/Fe 3O 4(001) interface

A. Pratt*, L. Dunne, X. Sun, M. Kurahashi, Y. Yamauchi

*Corresponding author for this work

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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.

Original languageEnglish
Article number07C114
JournalJournal of Applied Physics
Issue number7
Publication statusPublished - 1 Apr 2012

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