Purcell enhanced and blinking free single photons from InAs/GaAs quantum dots in deterministically placed circular Bragg gratings
The development of efficient, deterministic, and tunable single-photon sources is a cornerstone for the realization of long-distance quantum communication, quantum repeaters, and photonic quantum computing technologies. In this study, we demonstrate a bright, charge-tunable single-photon source in the 900 nm wavelength range based on InAs quantum dots (QDs) embedded in a p-i-n doped GaAs membrane, which shows blinking free emission. We use a modified circular Bragg grating (CBG) as a micro-resonator. By adding fourfold symmetric bridges in a labyrinth-like geometry, we provide a conductive pathway to the central disk, thereby enabling electrical contact to the QD while maintaining high Purcell enhancement and photon extraction efficiency (PEE). For the negative trion (X-), we demonstrate a lifetime of $44.3 \pm 0.2$ ps - corresponding to a Purcell factor of $18.0 \pm 0.7$ and a PEE of $68.1% \pm 3.1$ %. Furthermore, the device is blinking-free with very low multi-photon contribution, evidenced by a second-order autocorrelation value $g(2)(0) < 0.017 \pm 0.015$. By applying a vertical diode bias, we demonstrate precise charge-state control, resolving distinct emission plateaus ranging from the single negatively charged trion ($X^-$) to triply negatively charged excitons ($X^{3-}$). These results showcase a robust architecture that simultaneously provides high efficiency, high repetition rates, and deterministic charge control, fulfilling key requirements for the next generation of quantum network hardware.