Strain-tunable Single Photon Sources in WSe2 Monolayers
Sprache des Titels:
Englisch
Original Kurzfassung:
The appearance of single photon sources in atomically thin
semiconductors holds great promises for the development of a flexible and
ultracompact quantum technology in which elastic strain engineering can be used
to tailor their emission properties. Here, we show a compact and hybrid twodimensional
semiconductor-piezoelectric device that allows for controlling the
energy of single photons emitted by quantum emitters localized in wrinkled
WSe2 monolayers. We demonstrate that strain fields exerted by the piezoelectric
device can be used to tune the energy of localized excitons in WSe2 up to 18 meV
in a reversible manner while leaving the single photon purity unaffected over a
wide range. Interestingly, we find that the magnitude and, in particular, the sign of the energy shift as a function of stress is
emitter dependent. With the help of finite element simulations we suggest a simple model that explains our experimental
observations and, furthermore, discloses that the type of strain (tensile or compressive) experienced by the quantum emitters
strongly depends on their localization across the wrinkles. Our findings are of strong relevance for the practical implementation
of single photon devices based on two-dimensional materials as well as for understanding the effects of strain on their emission
properties.
Forschungs-