Schottky photodiodes based on mid-wavelength infrared intraband colloidal quantum dots - surface ligand and metal contact studies

Mohammad M. Al Mahfuz, Junsung Park, Rock Huebner, Sunghwan Lee, Dong Kyun Ko

Research output: Contribution to journalArticlepeer-review

Abstract

There is an emergent need for low-cost, uncooled detectors operating in the mid-wavelength infrared. Here, we report the first Schottky junction diode that utilizes intraband Ag2Se colloidal quantum dots as mid-wavelength infrared absorbers. These inexpensive, solution-processed Schottky devices exhibit orders-of-magnitude suppression of dark current compared to the photoconductors, while providing a greater fabrication simplicity compared to the barrier or p-n heterojunction devices. We highlight our findings on the role of the capping ligand in the detector performance parameters and discuss our metal contact studies to form rectifying junctions to the colloidal quantum dot films. The optimized Schottky devices show a favorable infrared responsivity of 0.1 A W−1 and an uncooled specific detectivity of 107 Jones. We also identify the present limitation of the device (1/f noise) and discuss potential paths toward future improvements.

Original languageEnglish (US)
Pages (from-to)7714-7721
Number of pages8
JournalJournal of Materials Chemistry C
Volume11
Issue number23
DOIs
StatePublished - May 22 2023

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Materials Chemistry

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