Observation of strong band bending in perylene tetracarboxylic dianhydride thin films grown on SnS2
| Autor: | Bruce A. Parkinson, Kenneth W. Nebesny, P. G. Schroeder, Neal R. Armstrong, M. W. Nelson, Paul A. Lee, Rudy Schlaf |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 86:1499-1509 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.370920 |
| Popis: | Perylene tetracarboxylic dianhydride (PTCDA) thin films were grown in several steps on tin disulfide (SnS2) single crystals and characterized by combined x-ray and ultraviolet photoemission spectroscopy (XPS), (UPS) in order to characterize the frontier orbital line-up and the interface dipole at their interface. Due to the large difference between the work functions of PTCDA (4.26 eV) and SnS2 (5.09 eV) this experiment represents a model system for the investigation of band bending related phenomena in organic semiconductor heterojunctions. Our results show that the equilibration between the Fermi levels of both materials in contact is achieved almost solely by band bending (bulk charge redistribution) in the PTCDA layer. No significant interface dipole was detected which means that the PTCDA molecular orbitals and the SnS2 bands align at the vacuum level corresponding to the electron affinity rule. Our experiments clearly demonstrate the importance of an additional XPS measurement which (in most cases) ... |
| Databáze: | OpenAIRE |
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