Growing Ultrathin Cu2O Films on Highly Crystalline Cu(111): A Closer Inspection from Microscopy and Theory

Trinh Thi Ly, Taehun Lee, Sanghwa Kim, Yun Jae Lee, Ganbat Duvjir, Kyuha Jang, Krisztián Palotás, Se Young Jeong, Aloysius Soon, Jungdae Kim

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Cu2O has been investigated for decades to understand the complex nature of oxidation and to utilize its high catalytic activity and intrinsic p-type character. However, the structures and intrinsic defects of Cu2O(111) surfaces have not been fully explored at the atomistic level, which is required to clarify some issues such as termination of Cu2O(111) surfaces. Here, our combined scanning tunneling microscopy (STM) and density functional theory (DFT) studies show that Cu2O(111) has a stoichiometric surface where the coordinately unsaturated Cu atoms appear with a hexagonal lattice. DFT simulations reflecting the orbital contributions of the STM tip present a good agreement with STM topography, unveiling the fine structures of Cu2O(111) surfaces that arise from coordinately saturated Cu atoms. Besides the possibility of kinetically formed oxygen vacancies reported in a previous work, two intrinsic defects identified in this work as a Cu vacancy (VCu) and Cu adatoms commonly exist on Cu2O(111) surfaces. Intriguingly, direct experimental evidence indicates that VCu plays the role of a hole provider in Cu2O. The topographic contrast of VCu is inverted by reversing the polarity of the sample bias, and VCu also exhibits strongly enhanced dI/dV spectrum at negative bias. These results imply that VCu is negatively charged due to its acceptor character. We expect that our observations will provide important information to establish an in-depth understanding of the fundamental properties of Cu2O.

Original languageEnglish
Pages (from-to)12716-12721
Number of pages6
JournalJournal of Physical Chemistry C
Volume123
Issue number20
DOIs
Publication statusPublished - 2019 May 23

Fingerprint

Ultrathin films
inspection
Microscopic examination
Inspection
Crystalline materials
microscopy
Scanning tunneling microscopy
scanning tunneling microscopy
Density functional theory
density functional theory
Atoms
Defects
Adatoms
reversing
defects
Oxygen vacancies
Topography
adatoms
Vacancies
atoms

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

Cite this

Ly, Trinh Thi ; Lee, Taehun ; Kim, Sanghwa ; Lee, Yun Jae ; Duvjir, Ganbat ; Jang, Kyuha ; Palotás, Krisztián ; Jeong, Se Young ; Soon, Aloysius ; Kim, Jungdae. / Growing Ultrathin Cu2O Films on Highly Crystalline Cu(111) : A Closer Inspection from Microscopy and Theory. In: Journal of Physical Chemistry C. 2019 ; Vol. 123, No. 20. pp. 12716-12721.
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abstract = "Cu2O has been investigated for decades to understand the complex nature of oxidation and to utilize its high catalytic activity and intrinsic p-type character. However, the structures and intrinsic defects of Cu2O(111) surfaces have not been fully explored at the atomistic level, which is required to clarify some issues such as termination of Cu2O(111) surfaces. Here, our combined scanning tunneling microscopy (STM) and density functional theory (DFT) studies show that Cu2O(111) has a stoichiometric surface where the coordinately unsaturated Cu atoms appear with a hexagonal lattice. DFT simulations reflecting the orbital contributions of the STM tip present a good agreement with STM topography, unveiling the fine structures of Cu2O(111) surfaces that arise from coordinately saturated Cu atoms. Besides the possibility of kinetically formed oxygen vacancies reported in a previous work, two intrinsic defects identified in this work as a Cu vacancy (VCu) and Cu adatoms commonly exist on Cu2O(111) surfaces. Intriguingly, direct experimental evidence indicates that VCu plays the role of a hole provider in Cu2O. The topographic contrast of VCu is inverted by reversing the polarity of the sample bias, and VCu also exhibits strongly enhanced dI/dV spectrum at negative bias. These results imply that VCu is negatively charged due to its acceptor character. We expect that our observations will provide important information to establish an in-depth understanding of the fundamental properties of Cu2O.",
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Ly, TT, Lee, T, Kim, S, Lee, YJ, Duvjir, G, Jang, K, Palotás, K, Jeong, SY, Soon, A & Kim, J 2019, 'Growing Ultrathin Cu2O Films on Highly Crystalline Cu(111): A Closer Inspection from Microscopy and Theory', Journal of Physical Chemistry C, vol. 123, no. 20, pp. 12716-12721. https://doi.org/10.1021/acs.jpcc.9b00255

Growing Ultrathin Cu2O Films on Highly Crystalline Cu(111) : A Closer Inspection from Microscopy and Theory. / Ly, Trinh Thi; Lee, Taehun; Kim, Sanghwa; Lee, Yun Jae; Duvjir, Ganbat; Jang, Kyuha; Palotás, Krisztián; Jeong, Se Young; Soon, Aloysius; Kim, Jungdae.

In: Journal of Physical Chemistry C, Vol. 123, No. 20, 23.05.2019, p. 12716-12721.

Research output: Contribution to journalArticle

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T2 - A Closer Inspection from Microscopy and Theory

AU - Ly, Trinh Thi

AU - Lee, Taehun

AU - Kim, Sanghwa

AU - Lee, Yun Jae

AU - Duvjir, Ganbat

AU - Jang, Kyuha

AU - Palotás, Krisztián

AU - Jeong, Se Young

AU - Soon, Aloysius

AU - Kim, Jungdae

PY - 2019/5/23

Y1 - 2019/5/23

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