Optical properties of MgNb2O6 single crystals

A comparison with LiNbO3

C. Zaldo, M. J. Martin, C. Coya, K. Polgar, A. Péter, J. Paitz

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

As-grown MgNb2O6 single crystals grown by the Czochralski method show a deep-blue colour due to the presence of broad optical absorption in the visible spectral region. The absorption of the samples is modified by thermal treatments in air and in vacuum. By heating in air the samples become transparent and by heating in a 1*10-2 mbar vacuum a complex and broad absorption is induced. An energy band gap of 5.25+or-0.15 eV has been determined. Oxidized samples have an absorption edge at 4.20 eV (at 15 K) but some pre-edge absorption is also present. This latter absorption and the associated photoluminescence emission with a maximum at 2.5 eV are attributed to interstitial Nb ions or Nb ions in Mg lattice sites. The optical absorptions induced by X-ray irradiation and vacuum reduction have been discussed in terms of the defects introduced. An absorption band at 2.30 eV induced by X-ray irradiation is attributed to holes trapped in oxygen (O--bound small polarons). The absorption band at 1.69 eV has been attributed to an electron trapped in Nb5+ ions (Nb4+ small polarons). Another absorption observed at 1.20 eV has been ascribed to a Mg-related electron trap centre. The possible presence of bipolaron centres and other electronic traps is discussed. A comparison with the optical absorption bands observed in LiNbO3 crystals has been established.

Original languageEnglish
Article number002
Pages (from-to)2249-2257
Number of pages9
JournalJournal of Physics Condensed Matter
Volume7
Issue number11
DOIs
Publication statusPublished - 1995

Fingerprint

Light absorption
Absorption spectra
Polarons
Optical properties
Single crystals
Vacuum
Ions
optical properties
single crystals
Irradiation
Heating
X rays
Electron traps
optical absorption
Crystal growth from melt
polarons
Air
absorption spectra
Band structure
vacuum

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Optical properties of MgNb2O6 single crystals : A comparison with LiNbO3. / Zaldo, C.; Martin, M. J.; Coya, C.; Polgar, K.; Péter, A.; Paitz, J.

In: Journal of Physics Condensed Matter, Vol. 7, No. 11, 002, 1995, p. 2249-2257.

Research output: Contribution to journalArticle

Zaldo, C. ; Martin, M. J. ; Coya, C. ; Polgar, K. ; Péter, A. ; Paitz, J. / Optical properties of MgNb2O6 single crystals : A comparison with LiNbO3. In: Journal of Physics Condensed Matter. 1995 ; Vol. 7, No. 11. pp. 2249-2257.
@article{488c41ac8c2c4fb2b7b9123d6ec88507,
title = "Optical properties of MgNb2O6 single crystals: A comparison with LiNbO3",
abstract = "As-grown MgNb2O6 single crystals grown by the Czochralski method show a deep-blue colour due to the presence of broad optical absorption in the visible spectral region. The absorption of the samples is modified by thermal treatments in air and in vacuum. By heating in air the samples become transparent and by heating in a 1*10-2 mbar vacuum a complex and broad absorption is induced. An energy band gap of 5.25+or-0.15 eV has been determined. Oxidized samples have an absorption edge at 4.20 eV (at 15 K) but some pre-edge absorption is also present. This latter absorption and the associated photoluminescence emission with a maximum at 2.5 eV are attributed to interstitial Nb ions or Nb ions in Mg lattice sites. The optical absorptions induced by X-ray irradiation and vacuum reduction have been discussed in terms of the defects introduced. An absorption band at 2.30 eV induced by X-ray irradiation is attributed to holes trapped in oxygen (O--bound small polarons). The absorption band at 1.69 eV has been attributed to an electron trapped in Nb5+ ions (Nb4+ small polarons). Another absorption observed at 1.20 eV has been ascribed to a Mg-related electron trap centre. The possible presence of bipolaron centres and other electronic traps is discussed. A comparison with the optical absorption bands observed in LiNbO3 crystals has been established.",
author = "C. Zaldo and Martin, {M. J.} and C. Coya and K. Polgar and A. P{\'e}ter and J. Paitz",
year = "1995",
doi = "10.1088/0953-8984/7/11/002",
language = "English",
volume = "7",
pages = "2249--2257",
journal = "Journal of Physics Condensed Matter",
issn = "0953-8984",
publisher = "IOP Publishing Ltd.",
number = "11",

}

TY - JOUR

T1 - Optical properties of MgNb2O6 single crystals

T2 - A comparison with LiNbO3

AU - Zaldo, C.

AU - Martin, M. J.

AU - Coya, C.

AU - Polgar, K.

AU - Péter, A.

AU - Paitz, J.

PY - 1995

Y1 - 1995

N2 - As-grown MgNb2O6 single crystals grown by the Czochralski method show a deep-blue colour due to the presence of broad optical absorption in the visible spectral region. The absorption of the samples is modified by thermal treatments in air and in vacuum. By heating in air the samples become transparent and by heating in a 1*10-2 mbar vacuum a complex and broad absorption is induced. An energy band gap of 5.25+or-0.15 eV has been determined. Oxidized samples have an absorption edge at 4.20 eV (at 15 K) but some pre-edge absorption is also present. This latter absorption and the associated photoluminescence emission with a maximum at 2.5 eV are attributed to interstitial Nb ions or Nb ions in Mg lattice sites. The optical absorptions induced by X-ray irradiation and vacuum reduction have been discussed in terms of the defects introduced. An absorption band at 2.30 eV induced by X-ray irradiation is attributed to holes trapped in oxygen (O--bound small polarons). The absorption band at 1.69 eV has been attributed to an electron trapped in Nb5+ ions (Nb4+ small polarons). Another absorption observed at 1.20 eV has been ascribed to a Mg-related electron trap centre. The possible presence of bipolaron centres and other electronic traps is discussed. A comparison with the optical absorption bands observed in LiNbO3 crystals has been established.

AB - As-grown MgNb2O6 single crystals grown by the Czochralski method show a deep-blue colour due to the presence of broad optical absorption in the visible spectral region. The absorption of the samples is modified by thermal treatments in air and in vacuum. By heating in air the samples become transparent and by heating in a 1*10-2 mbar vacuum a complex and broad absorption is induced. An energy band gap of 5.25+or-0.15 eV has been determined. Oxidized samples have an absorption edge at 4.20 eV (at 15 K) but some pre-edge absorption is also present. This latter absorption and the associated photoluminescence emission with a maximum at 2.5 eV are attributed to interstitial Nb ions or Nb ions in Mg lattice sites. The optical absorptions induced by X-ray irradiation and vacuum reduction have been discussed in terms of the defects introduced. An absorption band at 2.30 eV induced by X-ray irradiation is attributed to holes trapped in oxygen (O--bound small polarons). The absorption band at 1.69 eV has been attributed to an electron trapped in Nb5+ ions (Nb4+ small polarons). Another absorption observed at 1.20 eV has been ascribed to a Mg-related electron trap centre. The possible presence of bipolaron centres and other electronic traps is discussed. A comparison with the optical absorption bands observed in LiNbO3 crystals has been established.

UR - http://www.scopus.com/inward/record.url?scp=0038803086&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0038803086&partnerID=8YFLogxK

U2 - 10.1088/0953-8984/7/11/002

DO - 10.1088/0953-8984/7/11/002

M3 - Article

VL - 7

SP - 2249

EP - 2257

JO - Journal of Physics Condensed Matter

JF - Journal of Physics Condensed Matter

SN - 0953-8984

IS - 11

M1 - 002

ER -