Long radiative lifetimes of excitons in monolayer transition-metal dichalcogenidesMX2(M= Mo, W;X= S, Se)
- 13 December 2017
- journal article
- research article
- Published by IOP Publishing in Applied Physics Express
- Vol. 11 (1) , 015201
Abstract
We studied the effective exciton radiative lifetimes of monolayer two-dimensional transition-metal dichalcogenides MX 2 (M = Mo, W; X = S, Se). The photoluminescence (PL) quantum yield and PL decay time were measured for monolayer MoS2, MoSe2, WS2, and WSe2 at room temperature. Effective exciton radiative lifetimes of >10 ns were determined from the PL quantum yield of 10−2 to 10−3 and the PL decay time of several hundred picoseconds. The results are explained on the basis of the long radiative lifetime of bright excitons at a low temperature limit, a finite exciton coherence area of several square nanometers, and the population of dark exciton states.Keywords
Funding Information
- Asahi Glass Foundation (H2702)
- Japan Society for the Promotion of Science (JP22740195, JP25400324, JP24681031, JP23340085, JP25610074, JP26107522, JP16H00910, JP15K13500, JP16H06331)
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