Fabrication and Characterization of Inverted Silicon Pyramidal Arrays with Randomly Distributed Nanoholes

Abstract

We report the fabrication, electromagnetic simulation and measurement of inverted silicon pyramidal arrays with randomly distributed nanoholes that act as an anti-reflectivity coating. The fabrication route combines the advantages of anisotropic wet etching and metal-assisted chemical etching. The former is employed to form inverted silicon pyramid arrays, while the latter is used to generate randomly distributed nanoholes on the surface and sidewalls of the generated inverted silicon pyramidal arrays. We demonstrate, numerically and experimentally, that such a structure facilitates the multiple reflection and absorption of photons. The resulting nanostructure can achieve the lowest reflectance of 0.45% at 700 nm and the highest reflectance of 5.86% at 2402 nm. The average reflectance in the UV region (250–400 nm), visible region (400–760 nm) and NIR region (760–2600 nm) are 1.11, 0.63 and 3.76%, respectively. The reflectance at broadband wavelength (250–2600 nm) is 14.4 and 3.4 times lower than silicon wafer and silicon pyramids. In particular, such a structure exhibits high hydrophobicity with a contact angle up to 132.4°. Our method is compatible with well-established silicon planar processes and is promising for practical applications of anti-reflectivity coating.

Fabrication of Polymethyl Methacrylate (PMMA) Hydrophilic Surfaces Using Combined Offset-Tool-Servo Flycutting and Hot Embossing Methods

“…This simplified processing method not only helps in cost reduction but also enhances production efficiency. Furthermore, the replicated inverted pyramid microstructure array on the PMMA surface not only significantly alters the wettability of the PMMA surface but also provides superior mechanical robustness compared with a pyramid microstructure array [24][25][26].…”

Efficient infrared sunlight absorbers based on gold-covered, inverted silicon pyramid arrays

“…This kind of nanostructuration of the metal–silicon interfaces has already been used to enhance the performance of Si solar cells. 15–18 Furthermore, inverted Si pyramid arrays have been successfully implemented as surface enhanced Raman scattering (SERS) substrates, either directly 19 or by serving as template for the preparation of upright bulk metallic pyramids 20 or pyramidal arrays made of perfectly piled gold nanoparticles. 21 For the purpose of this work, however, the ansatz of implementing both types of pyramids, covered with different metals (Au, Al and Cu), in internal-photoemission detectors is of great interest.…”