Luminescence in SrTiO₃ and LiNbO₃ Crystals Under High Density Pulsed Electron Excitation

Abstract

The time-resolved luminescence as well as stationary excited luminescence in SrTiO₃ (undoped, Nb and Pb doped) and LiNbO₃ (congruent and stoichiometric) single crystals was studied. The charge-transfer vibronic exciton in the regular oxy-anion site is suggested to be responsible for luminescence bands at 2.8 eV and 2.75 eV for SrTiO₃ and LiNbO₃ crystals respectively. It is suggested that luminescence band observed in SrTiO₃ at ∼2.2-2.3 eV above 80 K possibly is due to some defect common for all SrTiO₃ crystals studied.

Keywords:

• SrTiO₃
• LiNbO₃
• polarons
• excitons
• luminescence

Acknowledgement

This work has been supported by Latvian Council for Science (grant 01.0813) and Excellence Centre for Advanced Material Research and Technology (Riga, Latvia), LN00A015 of MSMT CR and Program of Presidium of RAS “Low dimensional quantum structures”. The authors are grateful to E. A. Kotomin and R. Eglitis for stimulating discussions.