Harnessing Exciton-Exciton Annihilation in Two-Dimensional Semiconductors

Abstract

Strong many-body interactions in two-dimensional (2D) semiconductors give rise to efficient exciton-exciton annihilation (EEA). This process is expected to result in the generation of unbound high energy carriers. Here, we report an unconventional photoresponse of van der Waals heterostructure devices resulting from efficient EEA. Our heterostructures, which consist of monolayer transition metal dichalcogenide (TMD), hexagonal boron nitride (hBN), and few-layer graphene, exhibit photocurrent when photoexcited carriers possess sufficient energy to overcome the high energy barrier of hBN. Interestingly, we find that the device exhibits moderate photocurrent quantum efficiency even when the semiconducting TMD layer is excited at its ground exciton resonance despite the high exciton binding energy and large transport barrier. Using ab initio calculations, we show that EEA yields highly energetic electrons and holes with unevenly distributed energies depending on the scattering condition. Our findings highlight the dominant role of EEA in determining the photoresponse of 2D semiconductor optoelectronic devices.

6 pages, 3 figures, two-column style

References in corpus (5)

• Mechanisms of photoconductivity in atomically thin MoS2
• Ultrafast Dynamics of Defect-Assisted Electron-Hole Recombination in Monolayer MoS2
• Electrical suppression of all nonradiative recombination pathways in monolayer semiconductors
• Nonlinear Photoluminescence in Atomically Thin Layered WSe2 Arising from Diffusion-Assisted Exciton-Exciton Annihilation
• Upconverted electroluminescence via Auger scattering of interlayer excitons in van der Waals heterostructures

Cited by in corpus (7)

• Collective Excitations in 2D Materials
• ReS2/h-BN/Graphene Heterostructure Based Multifunctional Devices: Tunnelling Diodes, FETs, Logic Gates & Memory
• Electrical detection of the flat band dispersion in van der Waals field-effect structures
• A comprehensive study of complex non-adiabatic exciton dynamics in MoSi${}_2$N${}_4$
• Trion-trion annihilation in monolayer WS${}_2$
• Charge-carrier thermalization in bulk and monolayer CdTe from first principles
• A quasi steady-state measurement of exciton diffusion lengths in organic semiconductors