Tuning Multi-Wavelength Reflection Properties of Porous Silicon Bragg Reflectors Using Silver-Nanoparticle-Assisted...

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Porous silicon (PS) is a versatile material for photonic applications.
• Fabricating PS with tunable multi-wavelength reflection remains a challenge.

Purpose of the Study:

• To develop a silver-nanoparticle-assisted electrochemical etching method for fabricating porous silicon Bragg reflectors.
• To achieve multi-wavelength reflection characteristics in porous silicon structures.

Main Methods:

• Utilized silver nanoparticles (0.1-10 mg/mL) in HF-ethanol electrolyte.
• Applied periodically modulated current densities (40/100 mA/cm²).
• Investigated the influence of etching cycles (4-20) and nanoparticle concentration.

Main Results:

• Successfully transitioned from single-peak to multi-peak reflection spectra.
• Achieved up to four distinct reflection bands at 10 mg/mL silver nanoparticle concentration.
• SEM revealed periodic multilayer structures; XPS confirmed metallic silver presence.

Conclusions:

• The proposed method is simple, controllable, and cost-effective for fabricating multifunctional photonic devices.
• The developed Bragg reflectors show potential for laser optics, solar cells, chemical sensing, and SERS.
• This approach enables precise control over optical properties through nanoparticle concentration and etching parameters.