Infrared photodetection based on monodisperse mercury telluride colloidal quantum dots

Abstract

HgTe colloidal quantum dots (CQDs) are appealing candidates for infrared photodetection due to their facile tuning of infrared absorption, solution-processability and compatibility with silicon electronics for imaging. Traditional HgTe CQD synthesis suffers from CQD aggregation or air-sensitive tellurium (Te) precursor. Here, monodisperse HgTe CQDs with sharp excitonic absorption edge and tunable response from 1.7 μm to 6.3 μm are synthesized via a ligand-engineered approach. Thanks to their accessible CQD surface, both the carrier concentration and polarity can be readily tuned by ligand-induced surface gating. The transport property studies present a record electron mobility up to 18 cm² V^-1 s^-1. Short wave infrared photodetectors achieve a high room-temperature detectivity beyond 10¹¹ Jones at the wavelength of 1550 nm. The synthesis strategy is expected to enrich the applications of HgTe CQDs and promote the fast development of CQD infrared detection technology.