Reactivity and morphology of vapor-deposited Al/polymer interfaces for organic semiconductor devices

Journal Article · Fri Feb 01 04:00:00 EST 2008 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2837883· OSTI ID:21064543

Demirkan, K; Mathew, A; Weiland, C; Opila, R L ^[1]; Reid, M ^[2]

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1. Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716 (United States)
2. Centre for Telecommunications Value-Chain Research, Stokes Institute, University of Limerick, Limerick (Ireland)

The chemistry and the morphology of metal-deposited organic semiconductor interfaces play a significant role in determining the performance and reliability of organic semiconductor devices. We investigated the aluminum metallization of poly(2-methoxy-5,2{sup '}-ethyl-hexyloxy-phenylene vinylene) (MEH-PPV), polystyrene, and ozone-treated polystyrene surfaces by chemical (x-ray and ultraviolet photoelectron spectroscopy) and microscopic [atomic force microscopy, scanning electron microscopy (SEM), focused ion beam (FIB)] analyses. Photoelectron spectroscopy showed the degree of chemical interaction between Al and each polymer; for MEH-PPV, the chemical interactions were mainly through the C-O present in the side chain of the polymer structure. The chemical interaction of aluminum with polystyrene was less significant, but it showed a dramatic increase after ozone treatment of the polystyrene surface (due to the formation of exposed oxygen sites). Results showed a strong relationship between the surface reactivity and the condensation/sticking of the aluminum atoms on the surface. SEM analysis showed that, during the initial stages of the metallization, a significant clustering of aluminum takes place. FIB analysis showed that such clustering yields a notably porous structure. The chemical and the morphological properties of the vapor-deposited Al on organic semiconductor surfaces makes such electrical contacts more complicated. The possible effects of surface chemistry and interface morphology on the electrical properties and reliability of organic semiconductor devices are discussed in light of the experimental findings.

• OSTI ID: 21064543
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 3 Vol. 103; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM
ATOMIC FORCE MICROSCOPY
CHEMICAL ANALYSIS
CHEMICAL VAPOR DEPOSITION
ELECTRIC CONTACTS
ELECTRICAL PROPERTIES
ION BEAMS
MORPHOLOGY
ORGANIC SEMICONDUCTORS
OXYGEN
OZONE
PHOTOELECTRON SPECTROSCOPY
POLYSTYRENE
POROUS MATERIALS
REACTIVITY
SCANNING ELECTRON MICROSCOPY
SEMICONDUCTOR DEVICES
ULTRAVIOLET RADIATION
VAPOR DEPOSITED COATINGS
X RADIATION