Modified vapor phase deposition technology for high-performance uncooled MIR PbSe detectors

Area of Science:

• Materials Science
• Semiconductor Physics
• Infrared Technology

Background:

• Low performance of middle infrared (MIR) PbSe detectors made with vapor phase deposition (VPD) hinders technological advancement and commercialization.
• Current VPD technology for PbSe detectors requires improvement to match the performance of chemical bath deposition (CBD) methods.

Purpose of the Study:

• To enhance the performance of VPD-fabricated PbSe detectors by mimicking microstructural features of high-performance CBD-PbSe detectors.
• To identify key microstructural factors influencing infrared sensitivity in PbSe detectors.
• To explore methods for improving detectivity (D*) by addressing microstructural defects.

Main Methods:

• Modified vapor phase deposition (VPD) process development.
• Microstructural analysis of PbSe detectors fabricated via different methods.
• Optimization of sensitization processes, including iodine sensitization.
• Performance characterization of PbSe detectors, focusing on peak detectivity (D*).

Main Results:

• Achieved a peak detectivity (D*) of 1.6 × 10^10 cm Hz^1/2 W^-1 at 298 K with the modified VPD process.
• Identified nanoparticle self-assembly structures and oriented rod-like crystals as crucial for IR sensitivity in VPD-PbSe.
• Demonstrated that eliminating voids formed during iodine sensitization offers significant potential for increasing VPD-PbSe detectivity.
• The modified VPD technology shows performance comparable to CBD-PbSe detectors.

Conclusions:

• The modified VPD process successfully replicates high-performance microstructural features in PbSe detectors.
• Understanding microstructural evolution, particularly void elimination, is key to boosting VPD-PbSe detectivity.
• This advancement provides a viable technical foundation for manufacturing megapixel uncooled lead-salt focal plane array (FPA) imagers and accelerates industrialization.