Fully Integrated Silicon Photonic Erbium-Doped Nanodiode for Few Photon Emission at Telecom Wavelengths

• Published in: Materials Vol. 16; no. 6; p. 2344
• Main Authors: Tavani, Giulio, Barri, Chiara, Mafakheri, Erfan, Franzò, Giorgia, Celebrano, Michele, Castriotta, Michele, Di Giancamillo, Matteo, Ferrari, Giorgio, Picciariello, Francesco, Foletto, Giulio, Agnesi, Costantino, Vallone, Giuseppe, Villoresi, Paolo, Sorianello, Vito, Rotta, Davide, Finazzi, Marco, Bollani, Monica, Prati, Enrico
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 15.03.2023; MDPI
• Subjects: CMOS; Electroluminescence; Erbium; erbium doping; Evaluation; Ion implantation; Light emitting diodes; Nanowires; Photon emission; Photonics; Photons; Quantum cryptography; quantum key distribution; Room temperature; Semiconductors; Silicon; silicon photonics; SOI (semiconductors); SOI diode; Superconductors; SOI diode; quantum key distribution; silicon photonics; erbium doping
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16062344

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.