Brightness and purity of a room-temperature single-photon source in the blue-green range.

We discuss a promising solid-state system that emits single photons at room temperature in the blue-green range, making it an attractive candidate for quantum communications in free space and underwater. The active element is a core-shell ZnSe tapered nanowire embedding a single CdSe quantum dot grown by molecular beam epitaxy. A patterned substrate enables a comprehensive study of a single nanowire using various methods. Our source shows potential for achieving a total brightness of 0.17 photon per pulse and anti-bunching with g(2)(0) < 0.3 within a restricted spectral window. Additionally, we analyze the impact of charged excitons on the g(2)(0) value in different spectral ranges.

The onset of tapering in the early stage of growth of a nanowire.

The early stage of growth of semiconductor nanowires is studied in the case where the sidewall adatoms have a short diffusion length due to a strong desorption. Experimental results are described for the growth of ZnSe nanowires by molecular beam epitaxy. They are discussed and interpreted using the Burton-Cabrera-Frank description of the propagation of steps along the sidewalls, and compared to other II-VI and III-V nanowires. The role of the growth parameters and the resulting shape of the nanowires (cylinder, cone, or both combined) are highlighted.