Bismuth-Doped Ag₂Te Colloidal Quantum Dots for High-Performance Shortwave-Infrared Photodetectors

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Silver telluride (Ag₂Te) quantum dots (QDs) show promise for short-wave-infrared (SWIR) photodetection due to their high responsivity and eco-friendliness.
• A key limitation of Ag₂Te QDs is their high defect density, which hinders photogenerated charge carrier utilization efficiency.

Purpose of the Study:

• To develop bismuth-doped Ag₂Te (Bi:Ag₂Te) quantum dots (QDs) to overcome the limitations of undoped Ag₂Te QDs.
• To investigate the effect of bismuth doping on the defect density and energy band structure of Ag₂Te QDs.
• To evaluate the performance of Bi:Ag₂Te QDs in SWIR photodetectors.

Main Methods:

• Synthesis of Bi:Ag₂Te QDs using a hot-injection doping technique.
• Characterization of the structural and optoelectronic properties of the synthesized QDs.
• Fabrication and testing of SWIR photodiodes utilizing the Bi:Ag₂Te QDs.

Main Results:

• Bismuth doping effectively suppressed trap states and modulated the energy band structure of Ag₂Te QDs.
• The developed Bi:Ag₂Te QDs exhibited excellent SWIR photodetection performance.
• Photodiodes demonstrated high external quantum efficiencies (11.2% at 0 V, 30% at 0.3 V) and a specific detectivity (D*) of 7.67 × 10¹⁰ Jones at 1460 nm.

Conclusions:

• Bi:Ag₂Te QDs represent a novel material for high-performance SWIR photodetectors.
• Doping strategies can effectively tune the optoelectronic properties of QDs for advanced applications.
• This work provides a valuable reference for developing next-generation photodetector materials.