Dynamic exciton funneling by local strain control in a monolayer semiconductor

Abstract

The ability to control excitons in semiconductors underlies numerous proposed applications, from excitonic circuits for computing and communications to polariton condensates to energy transport in photovoltaics. 2D semiconductors are particularly promising for room-temperature applications due to their large exciton binding energy. Their enormous stretchability gives rise to a strain-engineerable bandgap that has been used to induce static exciton flux in predetermined structures. However, dynamic control of exciton flux represents an outstanding challenge. Here, we introduce a method to tune the bandgap of suspended 2D semiconductors by applying a local strain gradient with a nanoscale tip. This strain allows us to locally and reversibly shift the exciton energy and to steer the exciton flux over micron-scale distances, as observed by wide-field imaging and time-resolved photoluminescence spectroscopy. We anticipate that the ability to strongly and dynamically modulate the bandgap of a semiconductor at the nanoscale not only marks an important experimental tool but will also open a broad range of new applications from information processing to energy conversion.

17 pages, 4 figures

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Cited by in corpus (11)

• Probing dark exciton navigation through a local strain landscape in a WSe${}_2$ monolayer
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• Interaction-driven transport of dark excitons in 2D semiconductors with phonon-mediated optical readout
• Exciton fine structure splitting and linearly polarized emission in strained transition-metal dichalcogenide monolayers
• Optical properties of exciton in two-dimensional transition metal dichalcogenide nanobubbles
• Nonlinear exciton drift in piezoelectric two-dimensional materials
• Diffusion-related lifetime of indirect excitons in diamond
• Coherent spin dynamics of excitons in strained monolayer semiconductors
• Electron dynamics in a 2D nanobubble: A two-level system based on spatial density
• Exciton diffusion and annihilation in nanophotonic Purcell landscapes
• Transient strain induced electronic structure modulation in a semiconducting polymer imaged by scanning ultrafast electron microscopy