Excitons dominate the optics of atomically-thin transition metal dichalcogenides and 2D van der Waals heterostructures. Interlayer 2D excitons, with an electron and a hole residing in different layers, form rapidly in heterostructures either via direct charge transfer or via Coulomb interactions that exchange energy between layers. Here, we report prominent intertube excitonic effects in quasi-1D van der Waals heterostructures consisting of C/BN/MoS2 core/shell/skin nanotubes. Remarkably, under pulsed infrared excitation of excitons in the semiconducting CNTs we observed a rapid (sub-picosecond) excitonic response in the visible range from the MoS2 skin, which we attribute to intertube biexcitons mediated by dipole-dipole Coulomb interactions in the coherent regime. On longer (>100ps) timescales hole transfer from the CNT core to the MoS2 skin further modified the MoS2's absorption. Our direct demonstration of intertube excitonic interactions and charge transfer in 1D van der Waals heterostructures suggests future applications in infrared and visible optoelectronics using these radial heterojunctions.
@article{arxiv.2104.09430,
title = {Intertube excitonic coupling in nanotube van der Waals heterostructures},
author = {M. G. Burdanova and M. Liu and M. Staniforth and Y. Zheng and R. Xiang and S. Chiashi and A. Anisimov and E. I. Kauppinen and S. Maruyama and J. Lloyd-Hughes},
journal= {arXiv preprint arXiv:2104.09430},
year = {2021}
}