High Carrier Mobility in HgTe Quantum Dot Solids Improves Mid-IR Photodetectors

Menglu Chen, Xinzheng Lan, Xin Tang, Yuanyuan Wang, Margaret H. Hudson, Dmitri V. Talapin*, Philippe Guyot-Sionnest

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

91 Citations (Scopus)

Abstract

Improved mid-infrared photoconductors based on colloidal HgTe quantum dots are realized using a hybrid ligand exchange and polar phase transfer. The doping can also be controlled n and p by adjusting the HgCl2 concentration in the ligand exchange process. We compare the photoconductive properties with the prior "solid-state ligand exchange" using ethanedithiol, and we find that the new process affords a ∼100-fold increase of the electron and hole mobility, a ∼100-fold increase in responsivity, and a ∼10-fold increase in detectivity. These photodetector improvements are primarily attributed to the increase in mobility (μ) because the optical properties are mostly unchanged. We show that the specific detectivity (D*) of a photoconductive device is expected to scale as μ. The application potential is further verified by long-term device stability.

Original languageEnglish
Pages (from-to)2358-2365
Number of pages8
JournalACS Photonics
Volume6
Issue number9
DOIs
Publication statusPublished - 18 Sept 2019
Externally publishedYes

Keywords

  • HgTe
  • colloidal quantum dots
  • high mobility
  • mid-infrared
  • photoconductor

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