Coupling of Infrared Active Colloidal Quantum Dots and Amorphous Selenium for Fast and Sensitive Photodetection

Håvard Mølnås, Atreyo Mukherjee, Haripriya Kannan, Zhihang Han, Vikash K. Ravi, Shlok J. Paul, Abdul K. Rumaiz, Wei Zhao, Amir H. Goldan, Ayaskanta Sahu

Research output: Contribution to journalArticlepeer-review

Abstract

Colloidal quantum dot (CQD) based infrared (IR) photodetectors offer facile wavelength tunability in the IR and low-cost fabrication. However, owing to their large surface areas, CQDs intrinsically have significant surface traps critically affecting the speed of CQD photodetectors, typically mediated through tedious surface passivation efforts. In this report, an alternative strategy involving coupling of near-IR photoactive lead sulfide CQDs with a thermally evaporated amorphous selenium (a-Se) hole transport layer is proposed. By separating the detector into a photon absorbing CQD region and a charge transport a-Se region, the study takes advantage of the extremely low noise, predominantly hole-only transport process in a-Se. A high 3 dB bandwidth of 2.5 MHz and a competitive specific detectivity of 2.5 × 1011 Jones at room temperature are demonstrated at 980 nm. This report serves as a first demonstration of strong coupling between an IR active CQD absorber and a-Se, which paves the path to obtain fast and highly photoresponsive IR photodetection in the future.

Original languageEnglish (US)
JournalAdvanced Functional Materials
DOIs
StateAccepted/In press - 2024

Keywords

  • amorphous selenium
  • bandwidth
  • colloidal quantum dot
  • infrared photodetector
  • lead sulfide

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • General Chemistry
  • Biomaterials
  • General Materials Science
  • Condensed Matter Physics
  • Electrochemistry

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