Dewetting-Assisted Patterning: A Lithography-Free Route to Synthesize Black and Colored Silicon

Abstract

We report the use of thermal dewetting to structure gold-based catalytic etching masks for metal-assisted chemical etching (MACE). The approach involves low-temperature dewetting of metal films to generate metal holey meshes with tunable morphologies. Combined with MACE, dewetting-assisted patterning is a simple, benchtop route to synthesize Si nanotubes, Si nanowalls, and Si nanowires with defined dimensions and optical properties. The approach is compatible with the synthesis of both black and colored nanostructured silicon substrates. In particular, we report the lithography-free fabrication of silicon nanowires with diameters down to 40 nm that support leaky wave-guiding modes, giving rise to vibrant colors. Additionally, micrometer-sized areas with tunable film composition and thickness were patterned via shadow masking. After dewetting and MACE, such patterned metal films produced regions with distinct nanostructured silicon morphologies and colors. To-date, the fabrication of colored silicon has relied on complicated nanoscale patterning processes. Dewetting-assisted patterning provides a simpler alternative that eliminates this requirement. Finally, the simple transfer of resonant SiNWs into ethanolic solutions with well-defined light absorption properties is reported. Such solution-dispersible SiNWs could open new avenues for the fabrication of ultrathin optoelectronic devices with enhanced and tunable light absorption.

Bacterial Cellulose–Based MOF Hybrid as a Sensitive Switch Off–On Luminescent Sensor for the Selective Recognition of l-Histidine

“…Heretofore, composites of ultrasmall quencher detachments (QDs) such as Au nanoclusters, N, S, P-CQDs, and Ln@MOFs have served as the luminescence “Turn Off-On’’ sensing materials to detect l -His and have attracted increasing attention for their excellent luminescence characteristics. As a result, the detection limits have significantly reduced, and the detection sensitivities have remarkably improved. − Moreover, confining LMOF particles into a polymer matrix to fabricate flexible LMOF-based polymers with no change in their inherent properties has revealed a feasible strategy for chemical luminescence sensing purposes. , …”

Au Nanoparticles@Si Nanowire Oligomer Arrays for SERS: Dimers Are Best

“…In the presence of hydrofluoric acid (HF), this active mask etches Si in a highly anisotropic fashion. MACE can successfully transfer a variety of metal nanostructure patterns into the silicon substrate and is often used to synthesize VA-SiNW arrays using metal holey meshes perforated with circular holes. ,,,,, MACE does not require expensive lab equipment, is cost-effective, relatively fast, and can be used with different catalyst composition and geometry, and substrate materials. ,,, Additionally, MACE is especially effective at preparing high-aspect-ratio Si nanostructures with smooth walls, and can be CMOS-compatible using appropriate etching masks. − …”