Two-dimensional transition metal dichalcogenides provide an attractive platform for studying strain-dependent exciton transport at room temperature due to large exciton binding energy and strong bandgap sensitivity to mechanical stimuli. Here we use Rayleigh-type surface acoustic waves to demonstrate controlled and directional exciton transport under the weak coupling regime at room temperature. We screen the in-plane piezoelectric field using photogenerated carriers to study transport under type-I bandgap modulation and measure a maximum exciton drift velocity of 600 m s–1. Furthermore, we demonstrate the precise steering of exciton flux by controlling the relative phase between the input RF excitation and exciton photogeneration. The results provide an important insight into the weak coupling regime between the dynamic strain wave and room-temperature excitons in a two-dimensional semiconductor system and pave the way to exciting applications of excitonic devices ranging from data communication and processing to sensing and energy conversion.
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The raw dataset from phase-synchronized diffusion measurements and CW PL measurements are available from the corresponding author upon reasonable request.
The code for processing the raw TCSPC data is available from the corresponding author upon reasonable request.
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We acknowledge the help and support from the Lurie Nanofabrication Facility at the University of Michigan, Ann Arbor, where the device fabrication was carried out. P.B.D. acknowledges partial support of this work by the Air Force Office of Scientific Research (AFOSR) award no. FA9550-17-1-0208 and by the Army Research Office under grant no. W911NF-21-1-0207. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan (grant no. JPMXP0112101001), and JSPS KAKENHI (grant nos. 19H05790, 20H00354 and 21H05233).
The authors declare no competing interests.
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Datta, K., Lyu, Z., Li, Z. et al. Spatiotemporally controlled room-temperature exciton transport under dynamic strain. Nat. Photon. 16, 242–247 (2022). https://doi.org/10.1038/s41566-021-00951-3
Nature Photonics (2022)