In-Synthesis Se-Stabilization Enables Defect and Doping Engineering of HgTe Colloidal Quantum Dots

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Mercury telluride (HgTe) colloidal quantum dots (CQDs) offer tunable infrared absorption and silicon compatibility for photodetectors.
• Improving the chemical stability of HgTe CQDs is crucial for high-performance devices.

Purpose of the Study:

• To develop a Se-stabilization strategy for HgTe CQDs.
• To enhance the colloidal stability, passivation, and doping tunability of HgTe CQDs.
• To improve the performance and stability of HgTe CQD-based infrared photodetectors.

Main Methods:

• Engineered precursor reactivity to achieve surface coating of Se on HgTe CQDs.
• Fabricated optimized p-i-n HgTe CQD infrared photodetectors.
• Evaluated photodetector performance including dark current and specific detectivity.

Main Results:

• Se-coating improved colloidal stability and passivation of HgTe CQDs.
• Optimized photodetectors exhibited ultra-low dark current (3.26 × 10⁻⁶ A cm⁻²) and high specific detectivity (5.17 × 10¹¹ Jones at ≈2 um).
• The Se stabilization effect was maintained in thin films, significantly enhancing device stability.

Conclusions:

• The in-synthesis Se-stabilization strategy is effective for improving HgTe CQD chemical stability.
• This approach enables the construction of high-performance, stable CQD photodetectors.
• The strategy has potential implications for other CQD-based optoelectronic devices.