Mankel, Eric ; Hein, Corinna ; Kühn, Maybritt ; Mayer, Thomas (2014)
Electric potential distributions in space charge regions of molecular organic adsorbates using a simplified distributed states model.
In: physica status solidi (a), 211 (9)
doi: 10.1002/pssa.201330432
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
We study the evolution of the electric surface potential for small molecular organic semiconductors adsorbed on different high-work function substrates using photoelectron spectroscopy. Usually, the surface potential of these materials shows a typical progression in dependence of the adsorbate layer thickness indicating the formation of a space charge region near the interface. We discuss the surface potential evolution on the basis of the commonly used Schottky model and a second model using a density of states distribution (DOS) in the adsorbed semiconductor energy gap. In order to derive an analytical solution, we simplify an existing approach for space charge regions at polymer contacts. This approach is based on tailing gap states in polymer adsorbates. We simplify it using a constant DOS distribution. The differences between the Schottky model and the simplified distributed states model will be discussed. Finally, both models are applied to measured values of the surface potential evolution of some exemplary organic molecules on different substrates. We find that the surface potential evolution of the simplified distributed states model describes the measured potential development more accurately than the Schottky model. The DOS is estimated in the framework of the model being between 1018 and 1019 cm−3 eV−1.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2014 |
| Autor(en): | Mankel, Eric ; Hein, Corinna ; Kühn, Maybritt ; Mayer, Thomas |
| Art des Eintrags: | Bibliographie |
| Titel: | Electric potential distributions in space charge regions of molecular organic adsorbates using a simplified distributed states model |
| Sprache: | Englisch |
| Publikationsjahr: | September 2014 |
| Verlag: | WILEY-VCH Verlag GmbH & Co. KGaA |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | physica status solidi (a) |
| Jahrgang/Volume einer Zeitschrift: | 211 |
| (Heft-)Nummer: | 9 |
| DOI: | 10.1002/pssa.201330432 |
| Kurzbeschreibung (Abstract): | We study the evolution of the electric surface potential for small molecular organic semiconductors adsorbed on different high-work function substrates using photoelectron spectroscopy. Usually, the surface potential of these materials shows a typical progression in dependence of the adsorbate layer thickness indicating the formation of a space charge region near the interface. We discuss the surface potential evolution on the basis of the commonly used Schottky model and a second model using a density of states distribution (DOS) in the adsorbed semiconductor energy gap. In order to derive an analytical solution, we simplify an existing approach for space charge regions at polymer contacts. This approach is based on tailing gap states in polymer adsorbates. We simplify it using a constant DOS distribution. The differences between the Schottky model and the simplified distributed states model will be discussed. Finally, both models are applied to measured values of the surface potential evolution of some exemplary organic molecules on different substrates. We find that the surface potential evolution of the simplified distributed states model describes the measured potential development more accurately than the Schottky model. The DOS is estimated in the framework of the model being between 1018 and 1019 cm−3 eV−1. |
| Freie Schlagworte: | organic semiconductors, photoelectron spectroscopy, Schottky model, space charge regions, surface potential |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Elektronische Materialeigenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Oberflächenforschung 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften |
| Hinterlegungsdatum: | 26 Feb 2015 10:22 |
| Letzte Änderung: | 26 Feb 2015 10:22 |
| PPN: | |
| Sponsoren: | Financial support from the German Ministry of Education and Research (BMBF) within the MESOMERIE (FKZ 13N10721) and the OPEG 2010 (FKZ 13N9714) projects is gratefully acknowledged. |
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