Fig. 5: Population recombination and valley polarization dynamics of interlayer excitons.
From: Interlayer exciton formation, relaxation, and transport in TMD van der Waals heterostructures
a Transient dynamics of interlayer excitons at 1.6 eV in coherently stacked and randomly stacked MoS2/WS2 heterobilayers42. b Schematic illustration of probing the electron (K valley of WS2 at 1.95 eV) and hole (K valley of WSe2 at 1.60 eV) dynamics in a WS2/WSe2 heterostructure using a pump energy of 1.58 eV91. The hole population relates to the sum of the K–K and K–Q exciton populations, while the electron population reflects only the K–K exciton population. ΔEK–Q represents the energy difference between the lowest-energy K–Q and K–K transitions. c Electron dynamics of WS2/WSe2 heterostructures with twist angles of 0° and 60° at 295 K91. The exciton dynamics of monolayer WS2 are also shown. d Electron dynamics as a function of temperature for WS2/WSe2 heterostructures with twist angles of 0° and 60°91. e Co-polarized (σ+, black curves) and cross-polarized (σ−, red curves) PL dynamics of interlayer excitons under σ+ excitation at selected gate voltages33. The valley polarization dynamics are shown in blue curves. f Valley polarization (VP) of the singlet and triplet interlayer excitons with opposite helicities in the MoSe2/WSe2 heterobilayer135. g Valley polarization dynamics of interlayer excitons in the MoSe2/WSe2 heterobilayer extending to ~μs time scale under an out-of-plane magnetic field (Bz)27. h Top: the interlayer exciton recombination kinetics for WS2/WSe2 heterostructures with 0, 1, 2, and 3 hBN intermediate layers, denoted HS0, HS1, HS2, and HS3, respectively; Bottom: the valley polarization lifetime in the WSe2 monolayer, HS0, HS1, and HS2160. a Reprinted with permission from ref. 42 [Macmillan Publishers Limited]. b–d Reprinted with permission from ref. 91 [Springer Nature Limited]. e Reprinted with permission from ref. 33 [American Association for the Advancement of Science]. f Reprinted with permission from ref. 135 [American Physical Society]. g Reprinted with permission from ref. 27 [Springer Nature Limited]. h Reprinted with permission from ref. 160 [American Chemical Society]
