Delayed recombination and excited state ionization of the Ce3+ activator in the SrHfO3 host

• Published in: Physica status solidi. PSS-RRL. Rapid research letters Vol. 7; no. 3; pp. 228 - 231
• Main Authors: Mihóková, Eva, Jarý, Vítězslav, Schulman, Lawrence S., Nikl, Martin
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01-03-2013; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Low temperature physics; Luminescence; Materials science; oxides; scintillators; SrHfO3; thermal ionization; tunneling; Ultraviolet radiation
• ISSN: 1862-6254; 1862-6270
• DOI: 10.1002/pssr.201206499

We determine the thermal ionization energy of the excited state of Ce3+ in a SrHfO3 host by a contactless optical method based on the measurement and analysis of delayed recombination decay following UV excitation. We show the applicability of the method for microcrystalline powder samples. The method provides a consistent value of thermal ionization energy of about 0.25 eV, as previously determined by a ther‐ mally stimulated luminescence (TSL) study after UV illumination. We reveal a low temperature contribution to the delayed recombination signal and address its origin. This contribution indicates a complex interaction of the luminescence center with the host lattice neighborhood and the presence of temperature independent losses of fast scintillation light. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Loss of fast scintillation light deteriorates scintillator performance. Its cause can be assessed through the temperature dependence of delayed recombination decay following ultraviolet excitation. There are two components: The high temperature contribution is due to thermal ionization of the emitting center and its analysis enables determination of the ionization energy, while the low temperature contribution is likely due to quantum tunneling between the recombination center and nearby traps.