Paraboloid Structured Silicon Surface for Enhanced Light Absorption: Experimental and Simulative Investigations

Area of Science:

• Materials Science
• Optics
• Surface Engineering

Background:

• Light trapping and scattering are crucial for optical device efficiency.
• Existing surface textures like pyramids and hemispheres have limitations in minimizing reflectance.
• Silicon (Si) surface texturing is vital for various optoelectronic applications.

Purpose of the Study:

• To present a novel optical model for simulating light trapping and scattering on paraboloid textured silicon surfaces.
• To experimentally verify the model by measuring reflectance of fabricated paraboloid textured Si surfaces.
• To compare the performance of paraboloid textures with other existing textures.

Main Methods:

• Developed an optical model for paraboloid texture simulation.
• Fabricated paraboloid textured Si surfaces using electrochemical etching in hydrofluoric acid, DMSO, and DI water.
• Measured surface reflectance under varying conditions and correlated with the height-to-diameter (h/D) ratio.

Main Results:

• The paraboloid texture surface demonstrated significantly lower reflectance compared to hemispherical, random pyramidal, and regular pyramidal surfaces.
• Reflectance was highly dependent on the h/D ratio, with a minimum of ~4% at 600 nm for an h/D of 3.75.
• Simulations predicted reflectance could be reduced to ~0.5% by decreasing texture separations.

Conclusions:

• The developed optical model accurately predicts the reflectance of paraboloid textured Si surfaces.
• Paraboloid textured surfaces offer superior light trapping and reduced reflectance compared to conventional textures.
• Periodic paraboloidal structures present a promising alternative for surface texturing in antireflection applications.