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Interface Behaviour and Work Function Modification of Self-Assembled Monolayers on Sn-Doped In₂O₃

Hubmann, Andreas ; Dietz, Dominik ; Brötz, Joachim ; Klein, Andreas (2021):
Interface Behaviour and Work Function Modification of Self-Assembled Monolayers on Sn-Doped In₂O₃. (Publisher's Version)
In: Surfaces, 2 (2), pp. 241-256. MDPI, e-ISSN 2571-9637,
DOI: 10.26083/tuprints-00019795,
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Item Type: Article
Origin: Secondary publication service
Status: Publisher's Version
Title: Interface Behaviour and Work Function Modification of Self-Assembled Monolayers on Sn-Doped In₂O₃
Language: English
Abstract:

The modification of the work function of Sn-doped In₂O₃ (ITO) by vacuum adsorption of 4-(Dimethylamino)benzoic acid (4-DMABA) has been studied using in situ photoelectron spectroscopy. Adsorption of 4-DMABA is self-limited with an approximate thickness of a single monolayer. The lowest work function obtained is 2.82±0.1 eV, enabling electron injection into many organic materials. In order to identify a potential influence of the ITO substrate surface on the final work function, different ITO surface orientations and treatments have been applied. Despite the expected differences in substrate work function and chemical bonding of 4-DMABA to the substrate, no influence of substrate surface orientation is identified. The resulting work function of ITO/4-DMABA substrates can be described by a constant ionization potential of the adsorbed 4-DMABA of 5.00±0.08 eV, a constant band alignment between ITO and 4-DMABA and a varying Fermi energy in the ITO substrate. This corresponds to the behaviour of a conventional semiconductor heterostructure and deviates from the vacuum level alignment of interfaces between organic compounds. The difference is likely related to a stronger chemical bonding at the ITO/4-DMABA interface compared to the van der Waals bonding at interfaces between organic compounds.

Journal or Publication Title: Surfaces
Journal volume: 2
Number: 2
Publisher: MDPI
Classification DDC: 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Electronic Structure of Materials (ESM)
11 Department of Materials and Earth Sciences > Material Science > Structure Research
Date Deposited: 29 Oct 2021 12:22
Last Modified: 29 Oct 2021 12:23
DOI: 10.26083/tuprints-00019795
Corresponding Links:
URN: urn:nbn:de:tuda-tuprints-197957
Additional Information:

Keywords: ITO; work function; self-assembled monolayer; band alignment

URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/19795
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