SWIR Quantum Dot PDs Has 80% QE and 10ns Response Time, but High Dark Current

Matter publishes EPFL and Toronto University paper "Colloidal quantum dot photodetectors with 10-ns response time and 80% quantum efficiency at 1,550 nm" by Maral Vafaie, James Z.Fan, Amin Morteza Najarian, Olivier Ouellette, Laxmi Kishore Sagar, Koen Bertens, Bin Sun, F. Pelayo García de Arquer, Edward H.Sargent.

"To date, CQD photodetectors operating in the short-wave IR have failed to provide the combination of high responsivity, detectivity, and fast temporal response. To advance this field, large-diameter CQDs are needed that combine passivation with efficient charge transport.

Here, we present an efficient ligand-exchange strategy tailored to large CQDs having a band gap of 0.8 eV. The new well-passivated stable colloidal quantum dots enable high-quality CQD photoactive layers with exceptional optoelectronic properties. As a result, short-wavelength IR photodetectors operating at 1,550 nm with a record external quantum efficiency, reasonable detectivity, and fast response time are demonstrated."