Black Silicon: Breaking through the Everlasting Cost vs. Effectivity Trade-Off for SERS Substrates

• Published in: Materials Vol. 16; no. 5; p. 1948
• Main Authors: Golubewa, Lena, Rehman, Hamza, Padrez, Yaraslau, Basharin, Alexey, Sumit, Sumit, Timoshchenko, Igor, Karpicz, Renata, Svirko, Yuri, Kuzhir, Polina
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27.02.2023; MDPI
• Subjects: Absorption cross sections; Absorptivity; black silicon; Cost analysis; Economic aspects; Environmental monitoring; etching; Gold; Light; nanostructures; Noble metals; Plasma etching; Raman spectroscopy; Reactive ion etching; Room temperature; Silicon; Silicon substrates; Simulation methods; Spectrum analysis; Surface chemistry; surface plasmon resonance; surface-enhanced Raman spectroscopy; United States > US; black silicon; etching; surface plasmon resonance; nanostructures; surface-enhanced Raman spectroscopy
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16051948

Black silicon (bSi) is a highly absorptive material in the UV-vis and NIR spectral range. Photon trapping ability makes noble metal plated bSi attractive for fabrication of surface enhanced Raman spectroscopy (SERS) substrates. By using a cost-effective room temperature reactive ion etching method, we designed and fabricated the bSi surface profile, which provides the maximum Raman signal enhancement under NIR excitation when a nanometrically-thin gold layer is deposited. The proposed bSi substrates are reliable, uniform, low cost and effective for SERS-based detection of analytes, making these materials essential for medicine, forensics and environmental monitoring. Numerical simulation revealed that painting bSi with a defected gold layer resulted in an increase in the plasmonic hot spots, and a substantial increase in the absorption cross-section in the NIR range.