Ultra-Low-Reflective, Self-Cleaning Surface by Fabrication Dual-Scale Hierarchical Optical Structures on Silicon

Abstract

An integrated functional anti-reflective surface is of great significance for optical and optoelectronic devices. Hence, its preparation has attracted great attention from many researchers. This study combined wet alkaline etching approaches and reactive ion etching (RIE) techniques to create a dual-scale hierarchical anti-reflective surface on silicon substrates. The effect of RIE time on surface morphology and optical performance was investigated using multiple characterization forms. The optimal parameters for the fabrication of dual-scale structures by the composite etching process were explored. The silicon surface with a dual-scale structure indicated excellent anti-reflective properties (minimum reflectivity of 0.9%) in the 300 to 1100 nm wavelength range. In addition, the ultra-low reflection characteristic of the surface remained prominent at incident light angles up to 60°. The simulated spectra using the finite difference time domain (FDTD) method agreed with the experimental results. Superhydrophobicity and self-cleaning were also attractive properties of the surface. The functionally integrated surface enables silicon devices to have broad application prospects in solar cells, light emitting diodes (LEDs), photoelectric detectors, and outdoor equipment.

Bio-Inspired Hierarchical Micro-/Nanostructures for Anti-Icing Solely Fabricated by Metal-Assisted Chemical Etching

“…The hierarchical micro-/nanostructure is crucial to the superhydrophobic property because the composite surface consists of solid surfaces and air pockets, which increases the contact angle of water [ 20 , 21 ]. Currently, hierarchical micro-/nanostructures consisting of different materials such as Si [ 22 ], SiO 2 [ 23 ], TiO 2 [ 24 ], SnO 2 [ 25 ], MgO [ 26 ] are being demonstrated and applied in superhydrophobic [ 27 ], self-cleaning [ 28 ], fog collection [ 29 ], oil-water separation [ 30 ], anti-icing [ 31 , 32 ], energy [ 33 , 34 , 35 , 36 ], and sensing [ 37 ] applications.…”

General Strategy toward Laser Single-Step Generation of Multiscale Anti-Reflection Structures by Marangoni Effect

“…In recent years, various types of micro-nanostructures inspired by nature have also attracted extensive attention [7,28,29]. The moth-eye effect and light trapping effect of multiscale structures can not only reduce the Fresnel reflection loss on the material surface but also change the direction of the incident light [30].…”