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A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
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Low-cost uncooled MWIR PbSe quantum dots photodiodes
Jijun Qiu1, Binbin Weng1, Lance L McDowell1
1School of Electrical and Computer Engineering, University of Oklahoma Norman Oklahoma 73019 USA jjqiu@dlut.edu.cn shi@ou.edu.
RSC Advances
|May 11, 2022
Summary
Researchers developed a low-cost mid-wave infrared (MWIR) photodiode using lead selenide quantum dots (PbSe-QDs) and cadmium sulfide (CdS). Post-annealing optimized performance, achieving a 4.2 μm cutoff wavelength and high detectivity at room temperature.
Area of Science:
- Materials Science
- Optoelectronics
- Nanotechnology
Background:
- Traditional mid-wave infrared (MWIR) photodiodes often rely on expensive molecular beam epitaxy (MBE) technology.
- Uncooled photodiodes offer advantages in terms of cost and operational complexity.
- Lead selenide quantum dots (PbSe-QDs) present a promising material for infrared detection due to their tunable bandgap.
Purpose of the Study:
- To fabricate and characterize an uncooled PbSe-QDs/CdS p-n heterojunction photodiode for MWIR applications.
- To investigate the effect of post-annealing on the photodiode's performance and spectral response.
- To explore the potential of novel transparent conductive electrodes for monolithic integration.
Main Methods:
- Wet-chemical synthesis of PbSe-QDs and CdS.
- Fabrication of a p-n heterojunction photodiode.
- Post-annealing treatment at 673 K in air.
- Characterization of spectral photoresponse, responsivity, and specific detectivity.
- Temperature-dependent spectral response analysis.
Main Results:
- A ligand-free PbSe-QDs/CdS photodiode was successfully fabricated.
- Post-annealing at 673 K resulted in a MWIR photoresponse with a 4.2 μm cutoff wavelength.
- At room temperature and zero bias, peak responsivity of 0.36 ± 0.04 A/W and specific detectivity of (8.5 ± 1) × 10^8 cm Hz^1/2/W were achieved.
- An abnormal intensity variation below 200 K was observed, attributed to a band alignment transition.
- Indium-doped cadmium selenide (CdSe:In) was identified as a suitable infrared transparent conductive electrode.
Conclusions:
- Wet-chemical synthesis provides a low-cost route for fabricating MWIR PbSe-QDs/CdS photodiodes.
- Post-annealing is crucial for optimizing photodiode performance and tailoring spectral response.
- The developed photodiode demonstrates significant potential for uncooled MWIR imaging applications.
- CdSe:In films offer a viable solution for monolithic integration of MWIR photodiodes onto silicon circuitry.
