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Title: Electronic and optical properties of TaO{sub 1-x}N{sub 1+x}-based alloys

Abstract

TaON is considered as a potential candidate as a visible-light responsive photocatalyst. We report the results of ab initio studies of electronic structure of TaON-based alloys. Specifically, we show that the position of conduction and valence band can be modified by varying the oxygen and nitrogen concentrations in TaO{sub 1-x}N{sub 1+x}. We find that the band gap decreases monotonically with the increase of N/O ratio. The band gap energy is decreased in monoclinic TaON from near 2.3 eV to just over 1.7 eV (i.e., by 35%) when N/O ratio is increased from 3/5 to 5/3. Our calculations show that the band gap reduces in a series of experimentally fabricated alloys ZrTa{sub 3}O{sub 5}N{sub 3}{yields}TaON{yields}YTa{sub 7}O{sub 7}N{sub 8}. The band gap reduction is mostly associated with the change in the position of the valence band due to the hybridization of N 2p states, while the conduction band consisting mostly of Ta 5d-states is not sensitive to N content. The calculated optical absorption spectra show reduction in the optical band gap with increasing N/O ratio. - Graphical abstract: Band gap energy of TaO{sub 1-x}N{sub 1+x} as a function of N/O ratio. Highlights: Black-Right-Pointing-Pointer The electronic and optical properties of TaON-based alloys aremore » studied using DFT. Black-Right-Pointing-Pointer The position of conduction and valence bands can be modified by varying N/O ratio. Black-Right-Pointing-Pointer The band gap decreases monotonically with the increase of N/O ratio in TaO{sub 1-x}N{sub 1+x}. Black-Right-Pointing-Pointer The band gap reduces in a series of fabricated alloys ZrTa{sub 3}O{sub 5}N{sub 3}{yields}TaON{yields}YTa{sub 7}O{sub 7}N{sub 8}. Black-Right-Pointing-Pointer The optical band gap decreases with the increase of N/O ratio.« less

Authors:
 [1];  [1]; ;  [1]
  1. Department of Physics, University of Nebraska at Omaha, Omaha, NE 68182 (United States)
Publication Date:
OSTI Identifier:
22150037
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 198; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTRA; ALLOYS; ELECTRONIC STRUCTURE; MONOCLINIC LATTICES; NITROGEN; OPTICAL PROPERTIES; OXYGEN

Citation Formats

Al-Aqtash, Nabil, Apostol, Florin, Mei, Wai-Ning, Sabirianov, Renat F., and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588. Electronic and optical properties of TaO{sub 1-x}N{sub 1+x}-based alloys. United States: N. p., 2013. Web. doi:10.1016/J.JSSC.2012.10.029.
Al-Aqtash, Nabil, Apostol, Florin, Mei, Wai-Ning, Sabirianov, Renat F., & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588. Electronic and optical properties of TaO{sub 1-x}N{sub 1+x}-based alloys. United States. https://doi.org/10.1016/J.JSSC.2012.10.029
Al-Aqtash, Nabil, Apostol, Florin, Mei, Wai-Ning, Sabirianov, Renat F., and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588. 2013. "Electronic and optical properties of TaO{sub 1-x}N{sub 1+x}-based alloys". United States. https://doi.org/10.1016/J.JSSC.2012.10.029.
@article{osti_22150037,
title = {Electronic and optical properties of TaO{sub 1-x}N{sub 1+x}-based alloys},
author = {Al-Aqtash, Nabil and Apostol, Florin and Mei, Wai-Ning and Sabirianov, Renat F. and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588},
abstractNote = {TaON is considered as a potential candidate as a visible-light responsive photocatalyst. We report the results of ab initio studies of electronic structure of TaON-based alloys. Specifically, we show that the position of conduction and valence band can be modified by varying the oxygen and nitrogen concentrations in TaO{sub 1-x}N{sub 1+x}. We find that the band gap decreases monotonically with the increase of N/O ratio. The band gap energy is decreased in monoclinic TaON from near 2.3 eV to just over 1.7 eV (i.e., by 35%) when N/O ratio is increased from 3/5 to 5/3. Our calculations show that the band gap reduces in a series of experimentally fabricated alloys ZrTa{sub 3}O{sub 5}N{sub 3}{yields}TaON{yields}YTa{sub 7}O{sub 7}N{sub 8}. The band gap reduction is mostly associated with the change in the position of the valence band due to the hybridization of N 2p states, while the conduction band consisting mostly of Ta 5d-states is not sensitive to N content. The calculated optical absorption spectra show reduction in the optical band gap with increasing N/O ratio. - Graphical abstract: Band gap energy of TaO{sub 1-x}N{sub 1+x} as a function of N/O ratio. Highlights: Black-Right-Pointing-Pointer The electronic and optical properties of TaON-based alloys are studied using DFT. Black-Right-Pointing-Pointer The position of conduction and valence bands can be modified by varying N/O ratio. Black-Right-Pointing-Pointer The band gap decreases monotonically with the increase of N/O ratio in TaO{sub 1-x}N{sub 1+x}. Black-Right-Pointing-Pointer The band gap reduces in a series of fabricated alloys ZrTa{sub 3}O{sub 5}N{sub 3}{yields}TaON{yields}YTa{sub 7}O{sub 7}N{sub 8}. Black-Right-Pointing-Pointer The optical band gap decreases with the increase of N/O ratio.},
doi = {10.1016/J.JSSC.2012.10.029},
url = {https://www.osti.gov/biblio/22150037}, journal = {Journal of Solid State Chemistry},
issn = {0022-4596},
number = ,
volume = 198,
place = {United States},
year = {Fri Feb 15 00:00:00 EST 2013},
month = {Fri Feb 15 00:00:00 EST 2013}
}