Photocarrier recombination dynamics in highly excited SrTiO3 studied by transient absorption and photoluminescence spectroscopy

Abstract

We studied photocarrier recombination processes in highly excited SrTiO 3 crystals using pump-probe transient absorption ͑TA͒ and photoluminescence ͑PL͒ spectroscopy at room temperature. TA signals of nondoped SrTiO 3 crystals clearly appear in the visible and infrared spectral region under intense interband photoexcitation, and TA spectra show Drude-like photon-energy dependence. Both TA and PL decay curves are well explained by the same simple rate equation including three-body Auger recombination and single-carrier trapping.

Ultrafast Carrier Trapping of a Metal-Doped Titanium Dioxide Semiconductor Revealed by Femtosecond Transient Absorption Spectroscopy

“…[34][35][36][37][38] Our experimental setup to conduct highly sensitive transient absorption measurements executed by the pump-probe technique is displayed in Figure 3 A similar result was observed for other doped semiconductor materials. 6,16,[24][25][26]40 In these cases, the slow component is also attributed to the carrier trapping in the deeplevel energy states, which can attract electrons from the conduction band or holes from the valence band. Essentially, the time constants of both the fast and the slow component progressively decrease with increasing doping concentration.…”

Spatial density profile of electrons near the LaAlO3/SrTiO3 heterointerface revealed by time-resolved photoluminescence spectroscopy

“…[22][23][24][25][26] Strongly photoexcited or electron-doped SrTiO 3 shows a broad blue PL band at room temperature because of the radiative recombination of electrons and holes. The PL dynamics of SrTiO 3 can be explained on the basis of a simple model that includes nonradiative Auger recombination involving three carriers such as electron-electonhole.…”

Measurement of the Femtosecond Optical Absorption ofLaAlO3/SrTiO3Heterostructures: Evidence for an Extremely Slow Electron Relaxation at the Interface

“…It is known that electron-doped or photoexcited SrTiO 3 exhibits a broad optical absorption band in the infrared region [26][27][28]. The TA signal is observed under excitation at an energy above the band gap.…”