Exciton dynamics in WSe 2 bilayers Article - Novembre 2014

G. Wang, Xavier Marie, Louis Bouet, M. Vidal, Andrea Balocchi, Thierry Amand, D. Lagarde, B. Urbaszek

G. Wang, Xavier Marie, Louis Bouet, M. Vidal, Andrea Balocchi, Thierry Amand, D. Lagarde, B. Urbaszek, « Exciton dynamics in WSe 2 bilayers  », Applied Physics Letters, novembre 2014, p. 182105. ISSN 0003-6951

Abstract

We investigate exciton dynamics in WSe2 bilayers in time-resolved photoluminescence (PL) spectroscopy. Fast PL emission times are recorded for both the direct exciton with τD ≲ 3 ps and the indirect optical transition with τI ≈ 25 ps. For temperatures between 4 to 150 K τI remains constant. Following polarized laser excitation, we observe for the direct exciton transition at the K point of the Brillouin zone efficient optical orientation and alignment during the short emission time τD. The evolution of the direct exciton polarization and intensity as a function of excitation laser energy is monitored in PL excitation experiments.

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