Electrical Control of Single Photon Emitters in WSe₂ on a Si Nanopyramid Array with a Negligible Stark Effect

Single-photon emitters (SPEs) based on two-dimensional (2D) materials have attracted a lot of attention due to their unique benefits such as mechanical flexibility, high quantum yield, and easy integration on a chip. However, the electrical modulation of such emitters at a single-photon level still remains a challenge. Herein, we provide a new route to engineer electrically controllable purified SPEs in a monolayer (1L) WSe₂ using a Si nanopyramid structure. The Si nanopyramid structures allow not only the generation of high strain to localize the SPEs but also the application of voltage for electrical modulation. Of particular interest, while our structure modulates the single-photon emission with an applied gate voltage, it does not exhibit unwanted spectral shift for the applied voltage, i.e., a negligible Stark effect, due to the existence of an air gap between the 1L-WSe₂ and the nanopyramid. The single photon purity is improved by electrical modulation down to g⁽²⁾(0) = 0.06 ± 0.03.