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Unraveling the Gain Mechanism in High Performance Solution‐Processed PbS Infrared PIN Photodiodes
Author(s) -
Lee Jae Woong,
Kim Do Young,
So Franky
Publication year - 2015
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.201403673
Subject(s) - photodiode , materials science , dark current , photodetector , optoelectronics , infrared , specific detectivity , quantum efficiency , quantum tunnelling , evaporation , analytical chemistry (journal) , optics , chemistry , physics , chromatography , thermodynamics
High gain and low dark current solution‐processed colloidal PbS quantum dots infrared (IR) PIN photodetectors with IR sensitivity up to 1500 nm are demonstrated. The low dark current is due to the P‐I‐N structure with both electron and hole blockers. The high gain in our IR photodiodes is due to the enhancement of electron tunneling injection through the 1,1‐bis[(di‐4‐tolylamino) phenyl]cyclohexane (TAPC) electron blocker under IR illumination resulting from a distorted electron blocking barrier in the presence of photo‐generated holes trapped in the TAPC electron blocker. It is further found that the trap states in the TAPC layer are generated by the Ag atoms penetrated in the TAPC layer during the thermal evaporation process. The resulting photodetectors have a high detectivity value of 7 × 10 13 Jones, which is even higher than that of a commercial InGaAs photodiode.