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Highly conductive grain boundaries in copper oxide thin films

Deuermeier, Jonas ; Wardenga, Hans F. ; Morasch, Jan ; Siol, Sebastian ; Nandy, Suman ; Calmeiro, Tomás ; Martins, Rodrigo ; Klein, Andreas ; Fortunato, Elvira (2021):
Highly conductive grain boundaries in copper oxide thin films. (Publisher's Version)
In: Journal of Applied Physics, 119 (23), AIP Publishing, ISSN 0021-8979, e-ISSN 1089-7550,
DOI: 10.26083/tuprints-00019920,

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Item Type: Article
Origin: Secondary publication service
Status: Publisher's Version
Title: Highly conductive grain boundaries in copper oxide thin films
Language: English

High conductivity in the off-state and low field-effect mobility compared to bulk properties is widely observed in the p-type thin-film transistors of Cu₂O, especially when processed at moderate temperature. This work presents results from in situ conductance measurements at thicknesses from sub-nm to around 250 nm with parallel X-ray photoelectron spectroscopy. An enhanced conductivity at low thickness is explained by the occurrence of Cu(II), which is segregated in the grain boundary and locally causes a conductivity similar to CuO, although the surface of the thick film has Cu₂O stoichiometry. Since grains grow with an increasing film thickness, the effect of an apparent oxygen excess is most pronounced in vicinity to the substrate interface. Electrical properties of Cu₂O grains are at least partially short-circuited by this effect. The study focuses on properties inherent to copper oxide, although interface effects cannot be ruled out. This non-destructive, bottom-up analysis reveals phenomena which are commonly not observable after device fabrication, but clearly dominate electrical properties of polycrystalline thin films.

Journal or Publication Title: Journal of Applied Physics
Volume of the journal: 119
Issue Number: 23
Place of Publication: Darmstadt
Publisher: AIP Publishing
Collation: 8 Seiten
Classification DDC: 500 Naturwissenschaften und Mathematik > 530 Physik
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Surface Science
Date Deposited: 16 Nov 2021 12:38
Last Modified: 26 Jan 2023 12:09
DOI: 10.26083/tuprints-00019920
Corresponding Links:
URN: urn:nbn:de:tuda-tuprints-199208
URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/19920
PPN: 504067311
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