TY - JOUR
T1 - Effect of thermochemical treatments on laser-induced luminescence spectra from strontium titanate
T2 - comparison with swift ion-beam irradiation experiments
AU - Crespillo, M. L.
AU - Graham, J. T.
AU - Agulló-López, F.
AU - Zhang, Y.
AU - Weber, W. J.
N1 - Funding Information:
M.L.C. acknowledges financial support from the research project “Captación de Talento UAM” Ref: #541D300 supervised by Vice-Chancellor of Research of Universidad Autónoma de Madrid (UAM). This work was partially supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under Contract DE-AC05-00OR22725.
Funding Information:
M.L.C. acknowledges financial support from the research project ?Captaci?n de Talento UAM? Ref: #541D300 supervised by Vice-Chancellor of Research of Universidad Aut?noma de Madrid (UAM). This work was partially supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under Contract DE-AC05-00OR22725.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12
Y1 - 2021/12
N2 - Results recently reported on the effect of thermochemical treatments on the (He-Cd) laser-excited emission spectra of strontium titanate (STO) are re-analyzed here and compared with results obtained under ion-beam irradiation. Contributing bands centered at 2.4 eV and 2.8 eV, which appear under laser excitation, present intensities dependent upon previous thermal treatments in oxidizing (O2) or reducing atmosphere (H2). As a key result, the emission band centered at 2.8 eV is clearly enhanced in samples exposed to a reducing atmosphere. From a comparison with the ionoluminescence data, it is concluded that the laser-excited experiments can be rationalized within a framework developed from ion-beam excitation studies. In particular, the band at 2.8 eV, sometimes attributed to oxygen vacancies, behaves as expected for optical transitions from conduction-band (CB) states to the ground state level of the self-trapped exciton center. The band at 2.0 eV reported in ion-beam irradiated STO, and attributed to oxygen vacancies, is not observed in laser-excited crystals. As a consequence of our analysis, a consistent scheme of electronic energy levels and optical transitions can now be reliably offered for strontium titanate. Graphical abstract: [Figure not available: see fulltext.].
AB - Results recently reported on the effect of thermochemical treatments on the (He-Cd) laser-excited emission spectra of strontium titanate (STO) are re-analyzed here and compared with results obtained under ion-beam irradiation. Contributing bands centered at 2.4 eV and 2.8 eV, which appear under laser excitation, present intensities dependent upon previous thermal treatments in oxidizing (O2) or reducing atmosphere (H2). As a key result, the emission band centered at 2.8 eV is clearly enhanced in samples exposed to a reducing atmosphere. From a comparison with the ionoluminescence data, it is concluded that the laser-excited experiments can be rationalized within a framework developed from ion-beam excitation studies. In particular, the band at 2.8 eV, sometimes attributed to oxygen vacancies, behaves as expected for optical transitions from conduction-band (CB) states to the ground state level of the self-trapped exciton center. The band at 2.0 eV reported in ion-beam irradiated STO, and attributed to oxygen vacancies, is not observed in laser-excited crystals. As a consequence of our analysis, a consistent scheme of electronic energy levels and optical transitions can now be reliably offered for strontium titanate. Graphical abstract: [Figure not available: see fulltext.].
UR - http://www.scopus.com/inward/record.url?scp=85121868627&partnerID=8YFLogxK
UR - https://www.mendeley.com/catalogue/b7ce5c1b-f7df-3e1f-8f3a-175d9bb2200a/
U2 - 10.1140/epjd/s10053-021-00316-z
DO - 10.1140/epjd/s10053-021-00316-z
M3 - Article
AN - SCOPUS:85121868627
SN - 1434-6060
VL - 75
JO - European Physical Journal D
JF - European Physical Journal D
IS - 12
M1 - 314
ER -