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Temperature‐dependent optical absorption of SrTiO 3
Author(s) -
Kok Dirk J.,
Irmscher Klaus,
Naumann Martin,
Guguschev Christo,
Galazka Zbigniew,
Uecker Reinhard
Publication year - 2015
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201431836
Subject(s) - free carrier absorption , absorption edge , absorption (acoustics) , materials science , crystal (programming language) , melting point , attenuation coefficient , free electron model , extended x ray absorption fine structure , infrared , band gap , absorption spectroscopy , molecular physics , analytical chemistry (journal) , chemistry , optics , wavelength , optoelectronics , laser , physics , chromatography , computer science , composite material , programming language
The optical absorption edge and near infrared absorption of SrTiO3 were measured at temperatures from 4 to 1703 K. The absorption edge decreases from 3.25 eV at 4 K to 1.8 eV at 1703 K and is extrapolated to approximately 1.2 eV at the melting point (2350 K). The transmission in the near IR decreases rapidly above 1400 K because of free carrier absorption and is about 50% of the room temperature value at 1673 K. The free carriers are generated by thermal excitation of electrons over the band gap and the formation of charged vacancies. The observed temperature‐dependent infrared absorption can be well reproduced by a calculation based on simple models for the intrinsic free carrier concentration and the free carrier absorption coefficient. The measured red shift of the optical absorption edge and the rising free carrier absorption strongly narrow the spectral range of transmission and impede radiative heat transport through the crystal. These effects have to be considered in high temperature applications of SrTiO3 ‐based devices, as the number of free carriers rises considerably, and in bulk crystal growth to avoid growth instabilities. Temperature dependent optical absorption edge of SrTiO 3 , measured, fitted, and extrapolated to the melting point.