Uncooled and Broadband PbSe Colloidal-Quantum-Dot Short-Wave Infrared Photodetectors

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Solution-processed lead selenide colloidal quantum dots (PbSe CQDs) offer tunable band gaps and high carrier mobility for infrared photodetectors.
• Poor electronic properties have limited the performance of PbSe CQD-based photodetectors.

Purpose of the Study:

• To develop a novel strategy for enhancing the electronic properties of PbSe CQDs.
• To demonstrate high-performance infrared photodetectors and focal plane arrays using the improved PbSe CQDs.

Main Methods:

• A monomer-assisted ligand exchange (MLE) strategy was employed to modify PbSe CQDs.
• The MLE approach improved carrier mobility, carrier lifetime, and electronic uniformity of PbSe CQDs.

Main Results:

• PbSe CQD photodetectors achieved a record specific detectivity (D*) of 3.1 × 10^12 Jones at 1640 nm.
• The first 300,000-pixel focal plane arrays based on PbSe CQDs were demonstrated.
• Uncooled, broadband PbSe CQD photodetectors with photoresponses up to 2.5 μm were achieved, including a room-temperature D* of 3.0 × 10^11 Jones at ~2360 nm.

Conclusions:

• The MLE strategy effectively enhances PbSe CQD electronic properties, overcoming previous limitations.
• This advancement enables high-performance, large-format infrared photodetectors and broadband, uncooled detectors.
• The demonstrated PbSe CQD photodetectors show potential for surpassing existing technologies like InGaAs detectors in specific wavelength ranges.