Black phosphorus (BP) is an elemental layered material with a strong in-plane anisotropic structure. This structure is accompanied by anisotropic optical, electrical, thermal, and mechanical properties. Despite interest in BP from both fundamental and technical aspects, investigation into the structural dynamics of BP caused by strain fields, which are prevalent for two-dimensional (2D) materials and tune the material physical properties, has been overlooked. Here, we report the morphological dynamics of photoexcited BP membranes observed using time-resolved diffractograms and dark-field images obtained via ultrafast electron microscopy. Aided by 4D reconstruction, we visualize the nonequilibrium bulging of thin BP membranes and reveal that the buckling transition is driven by impulsive thermal stress upon photoexcitation in real time. The bulging, buckling, and flattening (on strain release) showed anisotropic spatiotemporal behavior. Our observations offer insights into the fleeting morphology of anisotropic 2D matter and provide a glimpse into the mapping of transient, modulated physical properties upon impulsive excitation, as well as strain engineering at the nanoscale.
|Number of pages||11|
|Publication status||Published - 2020 Sept 22|
Bibliographical noteFunding Information:
We thank Dong-gyu Kim and Sascha Schäfer for the AFM measurements and critical comments on this work, respectively. O.-H.K. and Y.-J.K. received support from the National Research Foundation of Korea (NRF) (NRF-2019R1A4A1027934 and NRF-2020R1A2C1014203). This work was also supported by the Institute for Basic Science (IBS-R020-D1), Korea, and by the Samsung Advanced Institute of Technology (SAIT)’s Global Research Outreach (GRO) Program. Y.L. and K.K. acknowledge support from the NRF (NRF-2017R1A5A1014862) and the Institute for Basic Science (IBS-R026-D1). We also acknowledge computational resources from UNIST-HPC.
© 2020 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physics and Astronomy(all)