Radiative lifetimes of excitons and trions in monolayers of the metal dichalcogenide MoS 2

By Haining Wang, Changjian Zhang, Weimin Chan, C. Manolatou, S. Tiwari, Farhan Rana. 2014

175 citations recorded by the source corpus.

We present results on the radiative lifetimes of excitons and trions in a monolayer of metal dichalcogenide MoS2. The small exciton radius and the large exciton optical oscillator strength result in radiative lifetimes in the 0.18-0.30 ps range for excitons that have small in-plane momenta and couple to radiation. Average lifetimes of thermally distributed excitons depend linearly on the exciton temperature and can be in the few picoseconds range at small temperatures and more than a nanosecond near room temperature. Localized excitons exhibit lifetimes in the same range and the lifetime increases as the localization length decreases. The radiative lifetimes of trions are in the hundreds of picosecond range and increase with the increase in the trion momentum. Average lifetimes of thermally distributed trions increase with the trion temperature as the trions acquire thermal energy and larger momenta. We expect our theoretical results to be applicable to most other 2D transition metal dichalcogenides.

Subfields: Biomedical Engineering, Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/cd28456af426dd3374c8e5cca5572084a2f6bd0e

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Citations in the corpus

• Valley excitons in two-dimensional semiconductors (2015, background): “by impurity or phonon scattering, and thus they act as a reservoir, so the ensemble averaged radiative lifetime could be significantly increased [60].”