Size-controlled fabrication of silicon nanopore arrays by silver-assisted chemical etching

Abstract

Silicon nanopore arrays are widely used in applications such as solution exchange, biomolecule detection, chemical analysis, and plant pathogen detection due to their high stability, long service life, and excellent compatibility with semiconductor and microfluidic technologies. However, existing fabrication methods such as wet etching, ion track etching, and electron beam lithography-assisted reactive ion etching face limitations, including poor size uniformity, uneven pore distribution, and high production costs. To address these challenges, this study proposes an improved metal-assisted chemical etching method for fabricating silicon nanopore arrays. This method combines silver nanoparticle-assisted etching with an anodic aluminum oxide template, promoting the orderly arrangement of silver nanoparticles on the silicon surface. By altering key factors such as nanoparticle size, etching time, temperature, and etchant oxidant concentration, the etching process was significantly optimized, with higher temperatures and oxidant concentrations accelerating nanopore formation. In addition, it is proposed that the anodic reaction likely involves the direct dissolution of silicon in its divalent state, with the gas generated during the etching process being a product of this reaction. Xenon lamp irradiation was used to fine-tune the etching kinetics, further optimizing the morphology of the silicon nanopores. The proposed technique is low-cost, highly adaptable, and reproducible, and has been successfully applied to design and optimize silicon nanopore arrays for various advanced applications. Compared to traditional industrial methods, this fabrication approach is more suitable for large-scale production, offering higher efficiency and better geometric control, making it ideal for applications in catalysis, sensing, and nanoelectronics.