Strain-tunable single-photon emission from an atomically thin semiconductor

One of the most unique mechanical properties of two-dimensional (2D) materials over conventional semiconductors is their high stretchability of more than 20% before fracture¹. Recently strain induced single photon emitters have been observed in 2D transition metal dichalcogenides^2-6. Tuning their emission energy is highly desired for efficient coupling to photonic devices. We demonstrate such tunability by engineering van der Waals heterostructure consisting of graphene/h-BN/WSe₂ on a piezoelectric actuator. Application of an electric field across the piezoelectric substrate induces a biaxial strain on the emitters hosted by the monolayer WSe₂ in the heterostructure. We have demonstrated a strain tunable energy shift of tens of meV using this approach.

1. Akinwande et al, Nature Communications, 5, 5678 (2014)
2. He et al, Nature Nanotechnology, 10, 497, (2015)
3. Chakraborty et al, Nature Nanotechnology, 10, 507, (2015)
4. Berraquero et al, Nature Communications 8, 15093 (2017)
5. Srivastava et al, Nature Nanotechnology 10, 491 (2015)
6. Koperski et al, Nature Nanotechnology 10, 503 (2015)