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Recent advancements in quantum key distribution (QKD) protocols opened the chance to exploit nonlaser sources for their implementation. A possible solution might consist in erbium-doped light emitting diodes (LEDs), which are able to produce photons in the third communication window, with a wavelength around 1550 nm. Here, we present silicon LEDs based on the electroluminescence of Er:O complexes in Si. Such sources are fabricated with a fully-compatible CMOS process on a 220 nm-thick silicon-on-insulator (SOI) wafer, the common standard in silicon photonics. The implantation depth is tuned to match the center of the silicon layer. The erbium and oxygen co-doping ratio is tuned to optimize the electroluminescence signal. We fabricate a batch of Er:O diodes with surface areas ranging from 1 µm × 1 µm to 50 µm × 50 µm emitting 1550 nm photons at room temperature. We demonstrate emission rates around 5 × 106 photons/s for a 1 µm × 1 µm device at room temperature using superconducting nanowire detectors cooled at 0.8 K. The demonstration of Er:O diodes integrated in the 220 nm SOI platform paves the way towards the creation of integrated silicon photon sources suitable for arbitrary-statistic-tolerant QKD protocols.
Publication date: 
15 Mar 2023

Giulio Tavani, Chiara Barri, Erfan Mafakheri, Giorgia Franzò, Michele Celebrano, Michele Castriotta, Matteo Di Giancamillo, Giorgio Ferrari, Francesco Picciariello, Giulio Foletto, Costantino Agnesi, Giuseppe Vallone, Paolo Villoresi, Vito Sorianello, Davide Rotta, Marco Finazzi, Monica Bollani, Enrico Prati

Biblio References: 
Volume: 16 Issue: 6 Pages: 2344