Premium
Optimization of Charge Carrier Extraction in Colloidal Quantum Dots Short‐Wave Infrared Photodiodes through Optical Engineering
Author(s) -
Georgitzikis Epimitheas,
Malinowski Pawel E.,
Maes Jorick,
Hadipour Afshin,
Hens Zeger,
Heremans Paul,
Cheyns David
Publication year - 2018
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201804502
Subject(s) - materials science , photodiode , optoelectronics , quantum dot , photodetector , lead sulfide , dark current , charge carrier , photoluminescence , infrared , band gap , quantum efficiency , optics , physics
Colloidal quantum dots (QDs) have attracted scientific interest for infrared (IR) optoelectronic devices due to their bandgap tunability and the ease of fabrication on arbitrary substrates. In this work, short‐wave IR photodetectors based on lead sulfide (PbS) QDs with high detectivity and low dark current is demonstrated. Using a combination of time‐resolved photoluminescence, carrier transport, and capacitance–voltage measurements, it is proved that the charge carrier diffusion length in the QD layer is negligible such that only photogenerated charges in the space charge region can be collected. To maximize the carrier extraction, an optical model for PbS QD‐based photodiodes is developed, and through optical engineering, the cavity at the wavelength of choice is optimized. This universal optimization recipe is applied to detectors sensitive to wavelengths above 1.4 µm, leading to external quantum efficiency of 30% and specific detectivity (D*) in the range of 10 12 Jones.