{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,3]],"date-time":"2026-07-03T23:56:22Z","timestamp":1783122982606,"version":"3.54.6"},"reference-count":27,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,10,22]],"date-time":"2025-10-22T00:00:00Z","timestamp":1761091200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Taichung Veterans General Hospital\/National Chi Nan University Joint Research Program","award":["TCVGH-NCNU-1137902"],"award-info":[{"award-number":["TCVGH-NCNU-1137902"]}]},{"name":"National Science and Technology Council, Taiwan","award":["NSTC 113-2221-E-260-003-MY2"],"award-info":[{"award-number":["NSTC 113-2221-E-260-003-MY2"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>This study proposes an innovative silver-nanoparticle-assisted electrochemical etching method for the fabrication of porous silicon Bragg reflectors with multi-wavelength reflection characteristics. By introducing silver nanoparticles at varying concentrations (0.1\u201310 mg\/mL) into the conventional HF\u2013ethanol electrolyte and applying periodically modulated current densities (40\/100 mA\/cm2), the transition from single-peak to multi-peak reflection spectra was successfully achieved. The results demonstrate that at a concentration of 10 mg\/mL silver nanoparticles, up to four distinct reflection bands can be obtained. A systematic investigation was conducted on the influence of etching cycles (4\u201320 cycles) and silver nanoparticle concentration on the optical performance and microstructure. SEM analysis revealed well-defined periodic multilayer structures, while XPS analysis confirmed the presence of metallic silver on the porous silicon surface. This work provides a simple, controllable, and cost-effective approach to the development of multifunctional photonic devices, with promising applications in laser optics, solar cells, chemical sensing, and surface-enhanced Raman scattering.<\/jats:p>","DOI":"10.3390\/mi16111198","type":"journal-article","created":{"date-parts":[[2025,10,23]],"date-time":"2025-10-23T01:14:02Z","timestamp":1761182042000},"page":"1198","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Tuning Multi-Wavelength Reflection Properties of Porous Silicon Bragg Reflectors Using Silver-Nanoparticle-Assisted Electrochemical Etching"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7344-5217","authenticated-orcid":false,"given":"Sheng-Yang","family":"Huang","sequence":"first","affiliation":[{"name":"Department of Surgery, Taichung Veterans General Hospital, Taichung 407219, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hsiao-Han","family":"Hsu","sequence":"additional","affiliation":[{"name":"Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Nantou 54561, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-9977-0754","authenticated-orcid":false,"given":"Amal","family":"Muhammed Musthafa","sequence":"additional","affiliation":[{"name":"Centre for Education (CFE), CSIR-Central Electrochemical Research Institute (CECRI), Karaikudi 630003, Tamil Nadu, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"I-An","family":"Lin","sequence":"additional","affiliation":[{"name":"Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Nantou 54561, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chia-Man","family":"Chou","sequence":"additional","affiliation":[{"name":"Department of Surgery, Taichung Veterans General Hospital, Taichung 407219, Taiwan"},{"name":"Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, Taichung 40227, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6121-7292","authenticated-orcid":false,"given":"Vincent K. S.","family":"Hsiao","sequence":"additional","affiliation":[{"name":"Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Nantou 54561, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2823","DOI":"10.1007\/s10853-010-4251-8","article-title":"Application of nanostructured porous silicon in the field of optics. A review","volume":"45","year":"2010","journal-title":"J. Mater. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Torres-Costa, V., and Mart\u00edn-Palma, R.J. (2021). Optical properties of porous silicon materials. 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