Design and Performance of an InAs Quantum Dot Scintillator with Integrated Photodetector

Area of Science:

• Materials Science
• Semiconductor Physics
• Radiation Detection

Background:

• Development of novel scintillation materials is crucial for advanced radiation detection.
• Indium Arsenide (InAs) quantum dots (QDs) offer tunable optical properties for scintillation applications.
• Integration of quantum dots with photodetectors (PDs) is essential for efficient signal readout.

Purpose of the Study:

• To develop and evaluate a new InAs quantum dot (QD) scintillation material hosted in a GaAs matrix.
• To design an integrated photodetector (PD) optimized for the QD emission spectrum.
• To assess the performance and radiation hardness of the developed scintillation material.

Main Methods:

• Fabrication of InAs QDs within a GaAs matrix.
• Design and integration of a photodetector using an InAlGaAs metamorphic buffer layer.
• Photoluminescence (PL) collection efficiency measurement using scanning laser excitation.
• Detector response evaluation for alpha particles and photons.
• Radiation hardness testing under 1 MeV proton implantation.

Main Results:

• Achieved electron yields of 13 electrons/keV for alpha particles and 30-60 electrons/keV for photons.
• Observed energy resolution of 12% for alpha particles, limited by optical losses.
• Demonstrated improved radiation hardness for InAs QDs in an AlGaAs matrix compared to GaAs and InGaAs.
• PL quenching analysis revealed defect-induced non-radiative recombination.

Conclusions:

• The developed InAs QD/GaAs scintillation material shows potential for radiation detection.
• Optimized photodetector integration enhances signal collection efficiency.
• Embedding QDs in AlGaAs significantly improves radiation hardness, crucial for harsh environments.