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Atomic Layer Deposition of Al2O3 onto Sn-Doped In2O3: Absence of Self-Limited Adsorption during Initial Growth by Oxygen Diffusion from the Substrate and Band Offset Modification by Fermi Level Pinning in Al2O3

Bayer, Thorsten J. M. ; Wachau, André ; Fuchs, Anne ; Deuermeier, Jonas ; Klein, Andreas (2012):
Atomic Layer Deposition of Al2O3 onto Sn-Doped In2O3: Absence of Self-Limited Adsorption during Initial Growth by Oxygen Diffusion from the Substrate and Band Offset Modification by Fermi Level Pinning in Al2O3.
In: Chemistry of Materials, 24 (23), pp. 4503-4510. ISSN 0897-4756,
[Article]

Abstract

The growth of Al2O3 onto Sn-doped In2O3 (ITO) by atomic layer deposition (ALD) was studied in situ using X-ray photoelectron spectroscopy. Significant diffusion of oxygen from the substrate destroys the self-terminated monolayer adsorption of the metal precursor and results in a nominal initial growth per cycle of >1 nm. The observed mechanism precludes the preparation of monolayer thick Al2O3 films on ITO substrates by ALD. The energy band alignment at the ITO/Al2O3 interface is significantly different from that obtained when magnetron sputtering is used for the deposition of Al2O3 onto ITO [Gassenbauer et al., Phys. Chem. Chem. Phys.2009, 11, 3049]. The difference is attributed to a pinning of the Fermi level in the ALD-Al2O3 layer close to midgap, which is attributed to the incorporation of hydrogen in the film during growth.

Item Type: Article
Erschienen: 2012
Creators: Bayer, Thorsten J. M. ; Wachau, André ; Fuchs, Anne ; Deuermeier, Jonas ; Klein, Andreas
Title: Atomic Layer Deposition of Al2O3 onto Sn-Doped In2O3: Absence of Self-Limited Adsorption during Initial Growth by Oxygen Diffusion from the Substrate and Band Offset Modification by Fermi Level Pinning in Al2O3
Language: English
Abstract:

The growth of Al2O3 onto Sn-doped In2O3 (ITO) by atomic layer deposition (ALD) was studied in situ using X-ray photoelectron spectroscopy. Significant diffusion of oxygen from the substrate destroys the self-terminated monolayer adsorption of the metal precursor and results in a nominal initial growth per cycle of >1 nm. The observed mechanism precludes the preparation of monolayer thick Al2O3 films on ITO substrates by ALD. The energy band alignment at the ITO/Al2O3 interface is significantly different from that obtained when magnetron sputtering is used for the deposition of Al2O3 onto ITO [Gassenbauer et al., Phys. Chem. Chem. Phys.2009, 11, 3049]. The difference is attributed to a pinning of the Fermi level in the ALD-Al2O3 layer close to midgap, which is attributed to the incorporation of hydrogen in the film during growth.

Journal or Publication Title: Chemistry of Materials
Journal volume: 24
Number: 23
Uncontrolled Keywords: indium−tin oxide; AL2O3; atomic layer deposition; initial growth; interface properties; band alignment; hydrogen impurity
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Surface Science
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > D - Component properties > Subproject D3: Function and fatigue of oxide electrodes in organic light emitting diodes
11 Department of Materials and Earth Sciences > Material Science
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > D - Component properties
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
11 Department of Materials and Earth Sciences
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Date Deposited: 16 Aug 2013 12:15
Official URL: http://dx.doi.org/10.1021/cm301732t
Additional Information:

SFB 595 D3

Identification Number: doi:10.1021/cm301732t
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