Fast-response infrared photodetector based on PbS quantum dots for integrated photonic devices characterization

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Integrated photonic circuits offer advanced optical functionalities.
• Quantum dots (QDs) are promising for novel optoelectronic devices.
• Developing efficient photodetectors for integrated systems is crucial.

Purpose of the Study:

• To demonstrate a fast-response infrared lead sulfide (PbS) quantum dot (QD) photodetector.
• To integrate QDs onto photonic circuits for enhanced optical functions.
• To explore applications in spectroscopy and microresonator characterization.

Main Methods:

• Fabrication of PbS QD photodetectors using a low-cost layer-by-layer process on glass substrates.
• Systematic characterization of absorption properties of QD solutions, films, and detectors.
• Performance evaluation including responsivity, bandwidth, and rise time measurements.

Main Results:

• Achieved a responsivity of 0.16 A/W at -1 V bias for the PbS QD photodetector operating at 1550 nm.
• Demonstrated a -3 dB bandwidth of 4 kHz and a rise time of 86.7 µs.
• Successfully applied the photodetector in acetylene gas absorption spectroscopy and microresonator characterization, showing agreement with commercial detectors.

Conclusions:

• This work presents a significant advancement in QD-integrated optoelectronic circuits.
• The developed photodetector is compatible with wafer-scale manufacturing and telecom wavelengths.
• Enables complex integrated photonic systems for sensing, communication, and computing.