Comprehensive Study of Au Nano-Mesh as a Catalyst in the Fabrication of Silicon Nanowires Arrays by Metal-Assisted Chemical Etching

Abstract

Silicon nanowires (SiNWs) arrays have become one of low-dimensional structural nanomaterials for the preparation of high-performance optoelectronic devices with the advantages of highly efficient light trapping effect, carrier multiplication, and adjustable optical bandgap. The controlled growth of SiNWs determines their electrical and optical properties. The morphology of silicon nanowires fabricated by conventional metal-assisted chemical etching (MACE) involving the Ag-based etching process cannot be precisely controlled. Ultra-thin anodic aluminum oxide (AAO) is one of the new-pattern nanostructure assembly systems for the synthesis of nanomaterials. The synthesized nanostructure arrays can be tuned to exhibit different optical and electrical properties in a certain wavelength range by adjusting the AAO membrane parameters. In this paper, we demonstrate an ultra-thin Au nano-meshes array from a single hexagonal AAO membrane as a replication master instead of conventional Ag particles as etching catalyst. The extended ordered silicon nanowires arrays are fabricated by the selective chemical dissolution of nanoscale noble metal meshes that exhibit excellent anti-reflection performance in broadband wavelengths and a wide incidence angle.

Micro- and Nano-Fabrication by Metal Assisted Chemical Etching

“…The variations in the particles size and distribution can be attributed to the continuous gold oxidation and reduction, which implies its dissolution and reprecipitation may decrease the diameter polydispersity. Figure 3 shows the SEM micrographs collected after etching of the (100) (panels a, a'), (110) (panels b, b'), ( 111)B (panels c, c'), and (211) (panels d, d') surfaces. Similar results were discussed in a previous work [12], but the brief analysis presented here provides a better interpretation of photon recycling mechanism of the etched surface.…”

Effect of Surface Morphology Changes on Optical Properties of Silicon Nanowire Arrays

“…The qualified Au films can be obtained by accurately controlling the input current, sputtering time and sputtering number. The sputtering parameters are selected as follows: current 3 mA, time 110 s, sputtering twice under this condition [ 23 ]. The Au film formed in the experiment cannot be broken due to the surface tension of the solution, nor can the Au nanomeshes be blocked by Au particles due to the closure effect [ 24 ].…”

“…The silicon substrate covered with the spatial mesh ordering of Au films are placed in the etching solution ratio of H 2 O 2 :HF:H 2 O = 5:12:37 for 60 min [ 23 ]. The surface morphologies of various ordered structures were investigated via SEM; the geometry of the arrays is shown in Figure 2 , demonstrating the excellent uniformity over large area that can be fabricated by this method.…”

Silicon Nanowires Synthesis by Metal-Assisted Chemical Etching: A Review

“…Metal film can be deposited on Si wafer and used as a metal catalyst in a MACE approach. Several works report the use of metal film to offer several advantages in terms of geometry control, diameter, spacing, and density [ 79 , 99 , 112 , 113 , 114 ] compared to MACE approaches that involve layers of nanoparticles similarly to single step MACE (e.g., the silver salts). The metal geometry determines the formation of silicon nanostructures and self-assembly methods can also be used for masking.…”