Colossal Core/Shell CdSe/CdS Quantum Dot Emitters

Area of Science:

• Materials Science
• Quantum Optics
• Nanotechnology

Background:

• Scalable integration of single-photon sources is vital for quantum technologies.
• Deterministic positioning of traditional, small quantum dots (QDs) in photonic structures is challenging.
• Existing giant core/shell QDs (20-50 nm) have limitations in large-scale device integration.

Purpose of the Study:

• To develop a synthesis strategy for colossal core/shell quantum dots exceeding current size limitations.
• To investigate the morphology and growth conditions of these large quantum dots.
• To assess the suitability of colossal QDs as high-performance single-photon sources.

Main Methods:

• Stepwise high-temperature continuous injection synthesis method.
• Electron microscopy for morphological and structural analysis.
• Photoluminescence lifetime and second-order photon correlation measurements.

Main Results:

• Successfully synthesized colossal CdSe/CdS QDs ranging from 30 to 100 nm.
• Identified synthesis conditions for crystalline particles and factors leading to defects.
• Achieved long photoluminescence lifetimes (microseconds) and suppressed blinking at room temperature.
• Demonstrated high single-photon emission purity (g(2)(0) < 0.2) for QDs with 80-100 CdS monolayers.

Conclusions:

• Colossal QDs offer a promising pathway for scalable quantum photonic devices.
• The developed synthesis method enables precise control over QD size and morphology.
• These large QDs exhibit excellent properties for advanced single-photon applications.