$CdTe_{0.25}Se_{0.75}$ Quantum Dots as Efficient Room Temperature Single Photon Source for Quantum Technology

Abstract: Room temperature single photon sources (SPS) are crucial for developing the next generation quantum technologies. Quantum dots (QDs), recently, have been reported as promising materials as SPS at room temperature. By optimizing the single particle optical properties of a series of water-soluble, $CdTe_{x}Se_{1-x}$, here we provide an efficient SPS with increased single photon purity. The data revealed that second order photon correlation, $g^2(0)$ value decreases substantially from 0.21 in CdTe to 0.02 in $CdTe_{0.25}Se_{0.75}$ QDs. They also exhibited deterministic emissions with an increase in ON time exceeding 95% of the total time. This was accompanied by an increased photon count rate, substantially reduced blinking events, and extended single particle ON-time. The increased single photon emission in $CdTe_{x}Se_{1-x}$ is attributed to very fast electron trapping to dense trap states, which suppresses the multiexciton recombination.