Abstract
AbstractStrong intertube excitonic coupling is demonstrated in 1D van der Waals heterostructures by examining the ultrafast response of radial C/BN/MoS2 core/shell/skin nanotubes to femtosecond infrared light pulses. Remarkably, infrared excitation of excitons in the semiconducting carbon nanotubes (CNTs) creates a prominent excitonic response in the visible range from the MoS2 skin, even with infrared photons at energies well below the bandgap of MoS2. Via classical analogies and a quantum model of the light–matter interaction these findings are assigned to intertube excitonic correlations. Dipole–dipole Coulomb interactions in the coherent regime produce intertube biexcitons, which persist for tens of femtoseconds, while on longer timescales (>100 ps) hole tunneling—from the CNT core, through the BN tunnel barrier, to the MoS2 skin—creates intertube excitons. Charge transfer and dipole–dipole interactions thus play prominent roles on different timescales, and establish new possibilities for the multi‐functional use of these new nanoscale coaxial cables.
Highlights
Before addressing these questions, we first set the scene by describing the current state-of-the-art in 2D van der Waals (vdW) hetero-Atomically-thin semiconductors such as the transition metal structures
In this contribution we report a significant intertube excitonic response for nano-coaxial cables formed from 1D vdW heterostructures (Figure 1a), which were fabricated by chemical vapor deposition on free-standing CNT template films.[5,6,8]
If a coherent excitonic polarization is created in the CNT using an infrared pump pulse, one may predict that intertube biexcitons and intertube excitons form dynamically with different rates
Summary
We first set the scene by describing the current state-of-the-art in 2D vdW hetero-. The Coulomb interaction between quasiparticles dichalcogenides (TMDs) feature electron confinement in 2D is known to play a prominent role in 2D, for instance creand strong Coulomb interactions that produce large exciton ating interlayer excitons, with an electron and a hole residing binding energies.[1,2] In 2D van der Waals (vdW) heterostruc- in different materials.[9,10,11] Interlayer excitons are thought to tures dramatic modifications of the electronic and optical form rapidly either via direct charge transfer or via Coulomb properties are known to arise, leading to unique effects like interactions that exchange energy between layers With their unconventional superconductivity[3] and excitons confined larger polarizability and slower recombination than intralayer. It is of fundamental and applied interest to examine charge transfer and energy coupling processes in 1D nanomaterials, where the Coulomb interaction has a different functional form than 2D, and to determine the strength or rate of each process
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