Determination of the electronic structure of organic Schottky contacts by photoemission spectroscopy

Ruediger Schlaf; Lisa A. Crisafulli; Hideyuki Murata; Charles D. Merritt; Zakya H. Kafafi; Paul G. Schroeder; M. W. Nelson; B. A. Parkinson; Paul A. Lee; Ken W. Nebesny; Neal R. Armstrong

doi:10.1117/12.372709

17 December 1999 Determination of the electronic structure of organic Schottky contacts by photoemission spectroscopy

Ruediger Schlaf, Lisa A. Crisafulli, Hideyuki Murata, Charles D. Merritt, Zakya H. Kafafi, Paul G. Schroeder, M. W. Nelson, B. A. Parkinson, Paul A. Lee, Ken W. Nebesny, Neal R. Armstrong

Author Affiliations +

Proceedings Volume 3797, Organic Light-Emitting Materials and Devices III; (1999) https://doi.org/10.1117/12.372709
Event: SPIE's International Symposium on Optical Science, Engineering, and Instrumentation, 1999, Denver, CO, United States

Abstract

The alignment of the highest occupied and lowest unoccupied molecular orbitals (HOMO, LUMO) of the organic luminescent semiconductor Gaq₃ relative to the Fermi level of Au was determined by depositing a Gaq₃ thin film in a multi-step growth procedure on an Au foil. Before growth and after each deposition step the sample was characterized by combined x-ray and ultraviolet photoemission spectroscopy (XPS, UPS) measurements. Such measurements offer a direct way to determine the electronic structure of the interface. Our experiments demonstrate that this method allows distinguishing between band bending, charging and interface dipole related shifts in the UP-spectra. The additional XPS measurements allow the precise determination of the band bending occurring across the interface while comparison between XPS and UPS work function measurements allows one to pinpoint the organic film thickness dependent onset of charging phenomena. Our results show that the interface dipoles at Gaq₃ Schottky contacts with Au, Pt and Ag amount to 0.6 - 0.7 eV. Our experiments also show that final state screening shifts can be dismissed as insignificant in such orbital line-up measurements. This was shown at the chloroindium phthalocyanine (ClInPc)/highly oriented pyrolytic graphite (HOPG) interface where no such shifts were observed.

Citation Download Citation

Ruediger Schlaf, Lisa A. Crisafulli, Hideyuki Murata, Charles D. Merritt, Zakya H. Kafafi, Paul G. Schroeder, M. W. Nelson, B. A. Parkinson, Paul A. Lee, Ken W. Nebesny, and Neal R. Armstrong "Determination of the electronic structure of organic Schottky contacts by photoemission spectroscopy", Proc. SPIE 3797, Organic Light-Emitting Materials and Devices III, (17 December 1999); https://doi.org/10.1117/12.372709

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available