Ultralow Dark Currents in Avalanche Amorphous Selenium Photodetectors Using Solution-Processed Quantum Dot Blocking Layer

Haripriya Kannan, Jann Stavro, Atreyo Mukherjee, Sébastien Léveillé, Kim Kisslinger, Lizhu Guan, Lizhu Guan, Wei Zhao, Ayaskanta Sahu, Amir H. Goldan

Research output: Contribution to journalArticlepeer-review

Abstract

We propose a true solid-state alternative to the vacuum photomultiplier tube using amorphous selenium (a-Se) as the bulk avalanche i-layer. A-Se is a unique photosensing material in which carrier transport can be shifted entirely from localized to extended states where only holes get hot and undergo impact ionization, resulting in deterministic and non-Markovian avalanche gain. To achieve reliable and repeatable impact ionization gain without irreversible breakdown, a non-insulating metal oxide n-type hole-blocking/electron-transporting layer is needed. For the first time, we have deposited a solution-processed quantum dot (QD) hole blocking layer over an a-Se film at room temperature, without any surface or bulk crystallization. We have measured the lowest dark current density ever reported (30 pA/cm2 at the onset of avalanche) compared to any other solid-state avalanche sensor at room temperature. Our results provide new strategies for the development of advanced solid-state photomultipliers via efficient QD-based interface layers to fully exploit the deterministic avalanche properties of a-Se.

Original languageEnglish (US)
Pages (from-to)1367-1374
Number of pages8
JournalACS Photonics
Volume7
Issue number6
DOIs
StatePublished - Jun 17 2020

Keywords

  • amorphous selenium
  • avalanche gain
  • cerium oxide
  • colloidal quantum dot
  • impact ionization
  • leakage current

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biotechnology
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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