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Application of atomic layer deposited Al2O3as charge injection layer for high-permittivity dielectrics

Hillmann, Stephan and Rachut, Karsten and Bayer, Thorsten J. M. and Li, Shunyi and Klein, Andreas (2015):
Application of atomic layer deposited Al2O3as charge injection layer for high-permittivity dielectrics.
In: Semiconductor Science and Technology, pp. 024012(1-7), 30, (2), ISSN 0268-1242, [Online-Edition: http://dx.doi.org/10.1088/0268-1242/30/2/024012],
[Article]

Abstract

The current transport through (Ba,Sr)TiO3 (BST)/Al2O3 bilayer structures with Pt electrodes is studied using current–voltage measurements. Due to its low permittivity compared to BST the Al2O3 layer, which is deposited by atomic layer deposition (ALD), enables electron injection by tunneling at low thickness, such that transport becomes limited by the bulk conductivity of BST. A current rectification of up to 106 is observed at an Al2O3 thickness of 1.8 nm, indicating that hole transport does not contribute to the current. The measurements are complemented by the determination of the energy band alignment at the interface using photoelectron spectroscopy. A Fermi level pinning in the Al2O3 layer, which seems to be characteristic for ALD films, leads to a significant modification of the energy band alignment. This pinning does not prohibit electron injection, which relies on the potential drop across the Al2O3 layer.

Item Type: Article
Erschienen: 2015
Creators: Hillmann, Stephan and Rachut, Karsten and Bayer, Thorsten J. M. and Li, Shunyi and Klein, Andreas
Title: Application of atomic layer deposited Al2O3as charge injection layer for high-permittivity dielectrics
Language: English
Abstract:

The current transport through (Ba,Sr)TiO3 (BST)/Al2O3 bilayer structures with Pt electrodes is studied using current–voltage measurements. Due to its low permittivity compared to BST the Al2O3 layer, which is deposited by atomic layer deposition (ALD), enables electron injection by tunneling at low thickness, such that transport becomes limited by the bulk conductivity of BST. A current rectification of up to 106 is observed at an Al2O3 thickness of 1.8 nm, indicating that hole transport does not contribute to the current. The measurements are complemented by the determination of the energy band alignment at the interface using photoelectron spectroscopy. A Fermi level pinning in the Al2O3 layer, which seems to be characteristic for ALD films, leads to a significant modification of the energy band alignment. This pinning does not prohibit electron injection, which relies on the potential drop across the Al2O3 layer.

Journal or Publication Title: Semiconductor Science and Technology
Volume: 30
Number: 2
Uncontrolled Keywords: (Ba,Sr)TiO3, charge transport, Al2O3, band alignment
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Surface Science
DFG-Collaborative Research Centres (incl. Transregio)
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
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 > D - Component properties > Subproject D3: Function and fatigue of oxide electrodes in organic light emitting diodes
Date Deposited: 16 Feb 2015 15:52
Official URL: http://dx.doi.org/10.1088/0268-1242/30/2/024012
Additional Information:

SFB 595 D3

Identification Number: doi:10.1088/0268-1242/30/2/024012
Funders: This work was supported by the German Science Foundation (DFG) within the collaborative research center SFB 595 (Electrical Fatigue of Functional Materials) and by the, research training school GRK 1037 (Tunable Integrated Components for Microwaves and Optics: TICMO).
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