Fig. 4: Interlayer exciton lifetime.
From: Confinement of long-lived interlayer excitons in WS2/WSe2 heterostructures
a Lifetime measurement of interlayer excitons in the flat WS2/WSe2 heterostructure region at 4 K. The data are fitted by a single exponential (solid red curve) with a lifetime τ = 180.6 ± 3.5 μs. b Lifetime measurement of a confined interlayer exciton (1.39 eV emission peak from Fig. 3d). The solid red curve is a biexponential fit with two lifetimes τs = 59.4 ± 0.9 ns and τl = 389.1 ± 1.2 ns. The inset presents a three-level model with coupling between a bright state \(\left|b\right\rangle\) and a shelving state \(\left|s\right\rangle\), as discussed in Supplementary Note S8. c τs (dark grey bars) and τl (light grey bars) values extracted from biexponential fits to the lifetime measurements at the eight nanopillar locations in device A (indexed a–h). Error bars are fitting errors. The average value of τs (τl) across all nanopillars is 80 ns (2 μs). The inset maps the physical location of the nanopillars on the WS2/WSe2 heterostructure region. The reduction of lifetime for confined interlayer excitons as compared to delocalised is also seen in device B, see Supplementary Figs. S15d and S16d.
