Colloidal Indium Arsenide quantum dots as short-wave infrared single photon emitters

MOONSHOT aims at developing a novel single-photon emitting material that operates in the telecommunication wavelength range (1300-1600 nm, O- and C-bands) and is compliant with the “Restriction of Hazardous Substances in Electrical and Electronic Equipment” (RoHS).

The main motivation for such objective is that single-photon sources based on epitaxial quantum dots (QDs) are now a mature technology available on the market that is outperforming laser cooled atoms or spontaneous parametric down conversion via nonlinear crystals.

Yet, three major issues afflict epitaxial QDs: first, the epitaxial approach presents drawbacks in terms of limited throughput and CMOS incompatibility. Secondly, often the emission wavelength of epitaxial QDs for single-photon generation is limited to less than 1000 nm. Finally, single-photon sources based on this class of QDs require low-temperature operation (T ≈ 4K).

Colloidal QDs present similar light-emission properties to their epitaxial counterpart and they can tackle most of the drawbacks of the latter.

For example, solution processing enables controlled placement of QDs on-chip as well as very high throughput preparation via wet-chemistry approaches. In addition, colloidal QDs have the potential for operation beyond cryogenic temperatures.

Nonetheless, state-of-the-art colloidal QDs with shortwave infrared emission (SWIR, 750-1600 nm) contain either lead or mercury, which are severely restricted by the RoHS.

Indium arsenide (InAs) QDs are among the few SWIR-emitting RoHS-compliant materials; yet only a limited number of synthetic approaches lead to emissive QDs.

MOONSHOT will focus on developing highly emissive and blinking-free InAs colloidal QDs based on a synthetic route employing commercially available precursors.

MOONSHOT adopts a high-risk strategy to realize a new technology in the field of quantum light sources with an immediate outcome in the form of optimized single-photon SWIR emitting QDs.