TY  - JOUR
AU  - Andrä, Michael
AU  - Funck, Carsten
AU  - Raab, Nicolas
AU  - Rose, Marc‐André
AU  - Vorokhta, Mykhailo
AU  - Dvorˇák, Filip
AU  - Šmíd, Brˇetislav
AU  - Matolín, Vladimír
AU  - Mueller, David N.
AU  - Dittmann, Regina
AU  - Waser, R.
AU  - Menzel, Stephan
AU  - Gunkel, Felix
TI  - Effect of Cationic Interface Defects on Band Alignment and Contact Resistance in Metal/Oxide Heterojunctions
JO  - Advanced electronic materials
VL  - 6
IS  - 1
SN  - 2199-160X
CY  - Chichester
PB  - Wiley
M1  - FZJ-2019-05627
SP  - 1900808 -
PY  - 2020
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000496844200001
DO  - DOI:10.1002/aelm.201900808
UR  - https://juser.fz-juelich.de/record/866537
ER  -