InSb/InP Core–Shell Colloidal Quantum Dots for Sensitive and Fast Short-Wave Infrared Photodetectors

Colloidal quantum dot technology (CQD) is considered the main contender towards a low-cost high performance optoelectronic technology platform for applications in the short-wave infrared (SWIR) to enable 3D imaging, LIDAR night vision etc. in the consumer electronics and automotive markets.In order to unleash the full potential of this technology there is a need for a material that is environmentally friendly, thus RoHS compliant, and possesses adequate optoelectronic properties to deliver high performance devices.InSb CQDs hold great potential in view of their RoHS compliant nature and -in principle-facile access to the SWIR.However, to date progress in realizing high performance optoelectronic devices, including photodetectors (PDs) has been limited.Here, we have developed a synthesis for producing size-tunable InSb CQDs with distinct excitonic peaks spanning a wide range from 900 nm to 1750 nm.To passivate the surface defects and enhance the photoluminescence (PL) efficiency of InSb CQDs, we further designed a InSb/InP core-shell structure.By employing the InSb/InP core-shell CQDs in a photodiode device stack, we report on robust InSb CQD SWIR photodetectors that exhibit external quantum efficiency (EQE) of 25% at 1240 nm, a wide linear dynamic range exceeding 128 dB, photoresponse time of 70 ns, and specific detectivity of 4.4 × 10 11 Jones.