Defect-Free Sb-Doping in Bi₂O₂Se Achieves Two-Order-of-Magnitude Reduction in Saturation Intensity While Preserving...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Optoelectronics

Background:

• Bismuth Oxy-Selenide (Bi2O2Se) is a promising semiconductor with excellent electronic properties.
• Its nonlinear optical response at low intensities limits practical applications.
• Overcoming doping-induced performance trade-offs is key for materials advancement.

Purpose of the Study:

• To achieve precise antimony (Sb3+) doping in Bi2O2Se.
• To investigate the impact of Sb3+ doping on electronic structure and optical properties.
• To enhance nonlinear optical performance for photonic devices.

Main Methods:

• Solid-state reaction for Sb3+ doping of Bi2O2Se.
• First-principles calculations for electronic structure analysis.
• Transient absorption spectroscopy and nonlinear optical measurements.

Main Results:

• Sb3+ substitution reduced the bandgap without introducing defect states.
• Carrier relaxation time was prolonged.
• Modulation depth increased, and saturation intensity decreased by two orders of magnitude (47.2 to 0.53 kW cm⁻²).

Conclusions:

• Defect-free Sb doping optimizes Bi2O2Se for enhanced nonlinear optical performance.
• Doping preserves and enhances carrier mobility while drastically reducing saturation intensity.
• This enables low-power, high-performance nonlinear photonic devices, particularly in mode-locking systems.