Journal Article

FZJ-2019-05627

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Effect of Cationic Interface Defects on Band Alignment and Contact Resistance in Metal/Oxide Heterojunctions

Andrä, M. (Corresponding author)FZJ* ; Funck, C.FZJ* ; Raab, N. ; Rose, M. ; Vorokhta, M. ; Dvorˇák, F. ; Šmíd, B. ; Matolín, V. ; Mueller, D. N. ; Dittmann, R.FZJ* ; Waser, R.FZJ* ; Menzel, S.FZJ* ; Gunkel, F. (Corresponding author)FZJ*

2020
Wiley Chichester

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Please use a persistent id in citations: http://hdl.handle.net/2128/23864  doi:10.1002/aelm.201900808

Abstract: Heterojunctions between high‐work‐function metals and metal oxides typically lead to Schottky‐type transport barriers resulting from charge transfer between the neighboring materials. These yield versatile electronic functionality exploited for current rectification, memristive behavior, or photocatalysis. Height, width, and shape of the interfacial transport barrier are strongly affected by charge screening via ionic defects, which are often extremely difficult to probe. The ionic nature of a variable contact resistance in heterojunctions between Nb‐doped SrTiO3 (Nb:SrTiO3) and platinum is explored. A control of cationic vacancy defects at the interface is achieved by different annealing procedures in oxidizing and reducing conditions before establishing Pt/Nb:SrTiO3 heterojunctions. Detailed analysis of electronic transport across the heterojunctions reveal significantly varied transport barriers resulting from the cationic defect structure at the interface. These findings are supported by conductive‐tip atomic force microscopy and in situ photoemission spectroscopy showing diminished conductivity of the Nb:SrTiO3 surface and the formation of an insulating surface skin layer after oxygenation. At high doping level, oxygen stoichiometry cannot explain the observed behavior. The increased transport barrier height is therefore linked to strontium vacancy defects. The tailored cation disorder yields access to the ionic control of electronic transport in functional oxide heterojunctions.

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Contributing Institute(s):

1. Elektronische Materialien (PGI-7)
2. JARA-FIT (JARA-FIT)
3. Elektronische Eigenschaften (PGI-6)
4. JARA - HPC (JARA-HPC)

Research Program(s):

1. 524 - Controlling Collective States (POF3-524) (POF3-524)
2. Modelling the Valency Change Memory Effect in Resistive Switching Random Access Memory (RRAM) (jpgi70_20120501) (jpgi70_20120501)

Appears in the scientific report 2020

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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