High-Performance and Stable Colloidal Quantum Dots Imager via Energy Band Engineering.
basic_science · Level V
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- Record sourced from PubMed, PMID 37433227.
- Also identified by DOI 10.1021/acs.nanolett.3c01391.
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Abstract
Solution-processed colloidal quantum dot (CQD) photodiodes are compatible for monolithic integration with silicon-based readout circuitry, enabling ultrahigh resolution and ultralow cost infrared imagers. However, top-illuminated CQD photodiodes for longer infrared imaging suffer from mismatched energy band alignment between narrow-bandgap CQDs and the electron transport layer. In this work, we designed a new top-illuminated structure by replacing the sputtered ZnO layer with a SnO<sub>2</sub> layer by atomic layer deposition. Benefiting from matched energy band alignment and improved heterogeneous interface, our top-illuminated CQD photodiodes achieve a broad-band response up to 1650 nm. At 220 K, these SnO<sub>2</sub>-based devices exhibit an ultralow dark current density of 3.5 nA cm<sup>-2</sup> at -10 mV, reaching the noise limit for passive night vision. The detectivity is 4.1 × 10<sup>12</sup> Jones at 1530 nm. These SnO<sub>2</sub>-based devices also demonstrate exceptional operation stability. By integrating with silicon-based readout circuitry, our CQD imager realizes water/oil discrimination and see-through smoke imaging.