Air-stable short-wave infrared PbS colloidal quantum dot photoconductors passivated with Al2O3 atomic layer deposition

Abstract

A PbS colloidal quantum dot photoconductor with Al2O3 atomic layer deposition (ALD) passivation for air-stable operation is presented. Two different types of inorganic ligands for the quantum dots, S2− and OH−, are investigated. PbS/S2− photoconductors with a cut-off wavelength up to 2.4 μm are obtained, and a responsivity up to 50 A/W at 1550 nm is reported. The corresponding specific detectivity is ∼3.4 × 108 Jones at 230 K. The 3-dB bandwidth of the PbS/S2− and PbS/OH− photodetectors is 40 Hz and 11 Hz, respectively.