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Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection
Published on: October 13, 2017
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Efficient luminescent down-shifting detectors based on colloidal quantum dots for dual-band detection applications
Scott M Geyer1, Jennifer M Scherer, Nosipho Moloto
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
ACS Nano
|May 20, 2011
Summary
Quantum dots (QDs) enhance near UV detection in InGaAs photodetectors. A luminescent down-shifting (LDS) layer boosts external quantum efficiency (EQE) significantly, enabling new UV imaging applications.
Area of Science:
- Materials Science
- Optoelectronics
- Nanotechnology
Background:
- Indium Gallium Arsenide (InGaAs) photodetectors are sensitive to short-wavelength infrared light.
- Extending their sensitivity to the near ultraviolet (UV) spectral band is challenging.
- Colloidal quantum dots offer tunable optical properties for light manipulation.
Purpose of the Study:
- To sensitize InGaAs photodetectors to the near UV spectral band using a colloidal quantum dot (QD) luminescent down-shifting (LDS) layer.
- To quantify the improvement in external quantum efficiency (EQE) across the near UV spectrum.
- To demonstrate a UV-sensitive InGaAs imaging array and analyze optical resolution and bandwidth.
Main Methods:
- Fabrication of an LDS layer using PbS/CdS core/shell QDs embedded in PMMA.
- Integration of the LDS layer with an InGaAs photodetector.
- Characterization of EQE, optical resolution, and detector bandwidth under UV illumination.
- Development of a simple model to fit experimental EQE data.
Main Results:
- Achieved an average improvement in EQE from 1.8% to 21% across the near UV spectrum.
- Demonstrated a functional UV-sensitive InGaAs imaging array.
- Calculated the effect of the LDS layer on optical resolution.
- Characterized the detector bandwidth, showing it is limited by QD photoluminescence lifetime.
Conclusions:
- Colloidal QD-based LDS layers effectively sensitize InGaAs photodetectors to the near UV.
- Significant EQE enhancement is achievable, enabling new UV detection capabilities.
- The LDS layer's impact on optical resolution and bandwidth is understood and characterized.
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