Strain Engineering of Two-Dimensional Semiconductors

In this talk, I will present our work on deterministic straining and confinement of excitons in atomically-thin, two-dimensional (2D) semiconductors. More specifically, I will present predictable and reconfigurable strain engineering in atomically-thin WSe2 via three-dimensional (3D) wrinkle architectures. Strain exerted on WSe2 was periodically modulated to tensile and compressive strain at peaks and valleys of the wrinkles, respectively via 3D wrinkle architecture. Furthermore, owing to the deformable nature of the wrinkle architecture, the applied strain can be tuned reconfigurably by post stretching/releasing processes, with PL shift dynamically modulated. We also observed exciton transport across apex and valley of WSe2 as well as exciton localization at the apex due to strain gradient induced energy modulation of wrinkled WSe2. Finally, I will present extension of our strain modulation approach to interlayer excitons in MoS2/WSe2 vertical heterostructures as well as applications towards strained, deterministic single photon emitters.