Over-Stoichiometry in Heavy Metal Oxides: The Case of Iono-Covalent Tantalum Trioxides

Yun Jae Lee, Taehun Lee, Aloysius Soon

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Oxides of tantalum (common examples including TaO, TaO 2 , and Ta 2 O 5 ) are key oxide materials for modern electronic devices, such as dynamic random-access memory and field effect transistors. Of late, new forms of stable tantalum oxides have been proposed as two-dimensional nanosheet structures with a nonconventional stoichiometry of TaO 3 via soft-chemical delamination of RbTaO 3 . However, not much is known about the elusive nanosheet-structured TaO 3 , unlike other closely related common trioxides of W and Mo. In this work, using first-principles density functional theory calculations, we have studied various TaO 3 structures as inspired from previous theoretical and experimental studies and discuss their properties with respect to the more conventional oxide of tantalum, Ta 2 O 5 . We have calculated their thermodynamics and lattice properties and have found a new stable-layered β-TaO 3 and its exfoliated monolayer phase (β′). By further analyzing their electronic structures, we discuss the mixed iono-covalent bonding characteristics in the TaO 3 phases, challenging the conventional formal oxidation state model for metal oxides. Finally, we propose how these new TaO 3 oxide materials may be potentially useful in photodevice applications.

Original languageEnglish
Pages (from-to)6057-6064
Number of pages8
JournalInorganic Chemistry
Volume57
Issue number10
DOIs
Publication statusPublished - 2018 May 21

Fingerprint

Tantalum
heavy metals
Heavy Metals
tantalum
Stoichiometry
Oxides
metal oxides
stoichiometry
Nanosheets
oxides
Field effect transistors
tantalum oxides
Delamination
Electronic structure
Density functional theory
Monolayers
random access memory
Metals
Thermodynamics
Data storage equipment

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

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title = "Over-Stoichiometry in Heavy Metal Oxides: The Case of Iono-Covalent Tantalum Trioxides",
abstract = "Oxides of tantalum (common examples including TaO, TaO 2 , and Ta 2 O 5 ) are key oxide materials for modern electronic devices, such as dynamic random-access memory and field effect transistors. Of late, new forms of stable tantalum oxides have been proposed as two-dimensional nanosheet structures with a nonconventional stoichiometry of TaO 3 via soft-chemical delamination of RbTaO 3 . However, not much is known about the elusive nanosheet-structured TaO 3 , unlike other closely related common trioxides of W and Mo. In this work, using first-principles density functional theory calculations, we have studied various TaO 3 structures as inspired from previous theoretical and experimental studies and discuss their properties with respect to the more conventional oxide of tantalum, Ta 2 O 5 . We have calculated their thermodynamics and lattice properties and have found a new stable-layered β-TaO 3 and its exfoliated monolayer phase (β′). By further analyzing their electronic structures, we discuss the mixed iono-covalent bonding characteristics in the TaO 3 phases, challenging the conventional formal oxidation state model for metal oxides. Finally, we propose how these new TaO 3 oxide materials may be potentially useful in photodevice applications.",
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Over-Stoichiometry in Heavy Metal Oxides : The Case of Iono-Covalent Tantalum Trioxides. / Lee, Yun Jae; Lee, Taehun; Soon, Aloysius.

In: Inorganic Chemistry, Vol. 57, No. 10, 21.05.2018, p. 6057-6064.

Research output: Contribution to journalArticle

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