Photocarrier recombination and localization dynamics of LaAlO3/SrTiO3 heterostructures

Y. Yamada; H. K. Sato; Y. Hikita; H. Y. Hwang; Y. Kanemitsu

doi:10.1117/12.2038785

8 March 2014 Photocarrier recombination and localization dynamics of LaAlO₃/SrTiO₃ heterostructures

Y. Yamada, H. K. Sato, Y. Hikita, H. Y. Hwang, Y. Kanemitsu

Proceedings Volume 8987, Oxide-based Materials and Devices V; 898710 (2014) https://doi.org/10.1117/12.2038785
Event: SPIE OPTO, 2014, San Francisco, California, United States

Abstract

We summarized our recent studies on the optical properties of SrTiO₃ single crystals and LaAlO₃/SrTiO₃ (LAO/STO) heterostructures using time-resolved photoluminescence (PL) and transient absorption (TA) measurements at low temperatures. We observed sharp band-edge PL peaks both in electron-doped SrTi_1-xNb_xO₃ and LAO/STO samples, corresponding to the radiative recombination of doped electrons in the conduction band and photoexcited holes in the valence band. These results evidence the existence of free electrons in the SrTi _1-xNb_xO₃ single crystal and at the LAO/STO heterointerface. In SrTiO₃ single crystals, TA signal gradually appears within 40 ps, which corresponds to the energy relaxation of photoexcited free electrons into self-trapped polaron states. The polaron formation time is enhanced considerably at the LaAlO₃/SrTiO₃ heterointerface compared to bulk crystals. We discuss the interface effects on the electron relaxation dynamics in terms of the strong interface potential.

Citation Download Citation

Y. Yamada, H. K. Sato, Y. Hikita, H. Y. Hwang, and Y. Kanemitsu "Photocarrier recombination and localization dynamics of LaAlO₃/SrTiO₃ heterostructures", Proc. SPIE 8987, Oxide-based Materials and Devices V, 898710 (8 March 2014); https://doi.org/10.1117/12.2038785

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