Ultrafast free-carrier dynamics in Cu2ZnSnS4 single crystals studied using femtosecond time-resolved optical spectroscopy

L. Q. Phuong, M. Okano, Y. Yamada, G. Yamashita, T. Morimoto, M. Nagai, M. Ashida, A. Nagaoka, K. Yoshino, Y. Kanemitsu

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19 Citations (Scopus)

Abstract

We studied the dynamics of photogenerated carriers in Cu2ZnSnS4 (CZTS) single crystals using femtosecond transient reflectivity (TR) and optical pump-THz probe transient absorption (THz- TA) spectroscopy. The TR and THz-TA decay dynamics consistently showed that free carriers have long lifetimes of up to a few nanoseconds. The excitation-photon-energy-dependent TR measurements revealed a slow picosecond energy relaxation of free carriers to the band edge in CZTS. The relaxation and recombination dynamics of free carriers were affected by nonradiative recombinations at the surface. Our results revealed a global feature of energy relaxation and recombination processes of free carriers in CZTS single crystals.

Original languageEnglish
Article number231902
JournalApplied Physics Letters
Volume105
Issue number23
DOIs
Publication statusPublished - 2014 Dec 8

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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    Phuong, L. Q., Okano, M., Yamada, Y., Yamashita, G., Morimoto, T., Nagai, M., Ashida, M., Nagaoka, A., Yoshino, K., & Kanemitsu, Y. (2014). Ultrafast free-carrier dynamics in Cu2ZnSnS4 single crystals studied using femtosecond time-resolved optical spectroscopy. Applied Physics Letters, 105(23), [231902]. https://doi.org/10.1063/1.4903802