Improving Strain-localized GaSe Single Photon Emitters with Electrical Doping

Abstract

Exciton localization through nanoscale strain has been used to create highly efficient single-photon emitters (SPEs) in 2D materials. However, the strong Coulomb interactions between excitons can lead to nonradiative recombination through exciton–exciton annihilation, negatively impacting SPE performance. Here, we investigate the effect of Coulomb interactions on the brightness, single photon purity, and operating temperatures of strain-localized GaSe SPEs by using electrostatic doping. By gating GaSe to the charge neutrality point, the exciton–exciton annihilation nonradiative pathway is suppressed, leading to ∼60% improvement of emission intensity and an enhancement of the single photon purity g (2)(0) from 0.55 to 0.28. The operating temperature also increased from 4.5 K to 85 K consequently. This research provides insight into many-body interactions in excitons confined by nanoscale strain and lays the groundwork for the optimization of SPEs for optoelectronics and quantum photonics.

Sub‐Diffraction Correlation of Quantum Emitters and Local Strain Fields in Strain‐Engineered WSe2 Monolayers

“…[ 16,17,23 ] Toward this end, cathodoluminescence microscopy has been a powerful tool for correlative studies on the nanoscale; [ 24–26 ] however, the characterization of TMDs requires encapsulation with hBN to prevent electron beam‐induced damage and imaging of the stacked heterostructure is challenging due to electron beam‐induced excitation in each layer. [ 27 ] Super‐resolution near‐field microscopy has been used in combination with atomic force microscopy (AFM) to correlate the emission spectra with local strain induced by small nanobubbles with heights up to 20 nm, [ 28,29 ] but these techniques are practically limited to noncryogenic temperatures where SPEs are not visible. [ 30–33 ] Cryogenic studies, on the other hand, have not incorporated nanoscale strain correlations when analyzing SPE properties.…”