Fig. 11: Excitonic devices based on interlayer excitons.
From: Interlayer exciton formation, relaxation, and transport in TMD van der Waals heterostructures
a Polarization switching actions based on the interlayer excitons in a MoSe2/WSe2 heterostructure117. ΔIRL = IR − IL is the difference between the right (IR) and left (IL) circularly polarized emission intensities of the interlayer excitons. VTG is the gate voltage. b Type-II band alignment of the TMD vdW heterobilayer, forming a three-level system for lasing196. c Schematic illustration of a laser device with a MoSe2/WSe2 heterobilayer integrated in a silicon nitride grating resonator196. d Interlayer exciton lasing from the device in c at 5 K196. The shaded boxes represent the spectral range of interlayer (IX), MoSe2, and WSe2 exciton emission. e Schematic illustration of the fabricated MoS2/WSe2 heterobilayer-PhCC nanolaser96. PhCC photonic crystal cavity. f Interlayer exciton lasing from the device in e at room temperature96. The linewidth is ~2.26 nm. The inset shows the spontaneous emission of the interlayer exciton for comparison. g Linewidth of the interlayer exciton emission as a function of the pump power for the laser device in e96. h Light input–light output (L–L) curve showing the cavity interlayer exciton emission from the device in e with a kink, suggesting the onset of superlinear emission and lasing operation96. The spontaneous emission displays a linear dependence on the pump power. i Schematic illustration of the MoSe2/WSe2 moiré heterostructure with a moiré pattern for the realization of quantum emitters142. j PL spectrum of the moiré-trapped interlayer excitons formed in the MoSe2/WSe2 moiré heterostructure at 4 K142. k The second-order correlation function g(2)(τ) of a single emitter at 1.401 eV shown in j142. l Stark tuning of moiré-trapped interlayer excitons at different gate voltages142. m Schematic illustration of the interlayer exciton photodetector based on the WS2/HfS2 heterostructure on a doped silicon substrate197. n The peak responsivity of the interlayer exciton photodetector based on the WS2/HfS2 heterostructure (Vg = 0 V, Vds = −1.5 V and Idevice = 0.5 nW) and that of other reported 2D-based photodetectors in the visible and infrared range197. NIR near infrared, SWIR short-wavelength infrared, MWIR mid-wavelength infrared, LWIR long-wavelength infrared, FIR far infrared. o Specific detectivity as a function of wavelength for WS2/HfS2 photodetectors shown in i and the other commercially available photodetectors at room temperature, except the one at 340 K197. a Reprinted with permission from ref. 117 [Springer Nature Limited]. b–d Reprinted with permission from ref. 196 [Springer Nature Limited]. e–h Reprinted with permission from ref. 96 [American Association for the Advancement of Science]. i–l Reprinted with permission from ref. 142 [American Association for the Advancement of Science]. m–o Reprinted with permission from ref. 197 [Springer Nature Limited]
