TY - JOUR
T1 - Electronic band structure and ensemble effect in monolayers of linear molecules investigated by photoelectron spectroscopy
AU - Häming, M.
AU - Ziroff, J.
AU - Salomon, E.
AU - Seitz, O.
AU - Cahen, D.
AU - Kahn, A.
AU - Schöll, A.
AU - Reinert, F.
AU - Umbach, E.
PY - 2009/4/1
Y1 - 2009/4/1
N2 - The electronic band structure of different alkyl/Si(111) self-assembled monolayers (SAMs) was investigated using photoelectron spectroscopy (PES) with variable photon energy. We observe a significant dispersion in the valence-band spectra and a large density-of-states (DOS) effect. The dispersion can be described by quantum well states, which depend only on the local properties of the alkanes with a dispersion relation similar to polyethylene and without any significant influence of the Si/molecule interface. Furthermore, the DOS effect is due to averaging over molecules with different tilt angles and thus can be considered as indicator for the degree of orientational order within the SAM. Finally we present a structural model for a description of the PES data, which takes both aspects into account.
AB - The electronic band structure of different alkyl/Si(111) self-assembled monolayers (SAMs) was investigated using photoelectron spectroscopy (PES) with variable photon energy. We observe a significant dispersion in the valence-band spectra and a large density-of-states (DOS) effect. The dispersion can be described by quantum well states, which depend only on the local properties of the alkanes with a dispersion relation similar to polyethylene and without any significant influence of the Si/molecule interface. Furthermore, the DOS effect is due to averaging over molecules with different tilt angles and thus can be considered as indicator for the degree of orientational order within the SAM. Finally we present a structural model for a description of the PES data, which takes both aspects into account.
UR - http://www.scopus.com/inward/record.url?scp=65649148618&partnerID=8YFLogxK
U2 - 10.1103/physrevb.79.155418
DO - 10.1103/physrevb.79.155418
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AN - SCOPUS:65649148618
SN - 1098-0121
VL - 79
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 15
M1 - 155418
ER -