Blue light emission from strongly photoexcited and electron-doped SrTiO3

Abstract

We studied photoluminescence (PL) spectrum and dynamics of undoped and electron-doped SrTiO3. At low temperatures below 100 K, we observed two band-edge PL peaks and a broad PL band in strongly photoexcited SrTiO3 and electron-doped SrTiO3 samples. In electron-doped samples, the peak energy of the broad PL band depends on the excitation photon energy at low temperatures: it changes from 2.5 to 2.9 eV with the excitation photon energy. On the other hand, the PL dynamics is independent of the excitation photon energy and is explained by a simple model involving single-carrier trapping and Auger recombination. From the PL spectrum and dynamics under different excitation photon energies, the PL processes in SrTiO3 are discussed.