title: Chemically Roughened Solid Silver: A Simple, Robust and Broadband SERS Substrate.
abstract: Surface-enhanced Raman spectroscopy (SERS) substrates manufactured using complex nano-patterning techniques have become the norm. However, their cost of manufacture makes them unaffordable to incorporate into most biosensors. The technique shown in this paper is low-cost, reliable and highly sensitive. Chemical etching of solid Ag metal was used to produce simple, yet robust SERS substrates with broadband characteristics. Etching with ammonium hydroxide (NH₄OH) and nitric acid (HNO₃) helped obtain roughened Ag SERS substrates. Scanning electron microscopy (SEM) and interferometry were used to visualize and quantify surface roughness. Flattened Ag wires had inherent, but non-uniform roughness having peaks and valleys in the microscale. NH₄OH treatment removed dirt and smoothened the surface, while HNO₃ treatment produced a flake-like morphology with visibly more surface roughness features on Ag metal. SERS efficacy was tested using 4-methylbenzenethiol (MBT). The best SERS enhancement for 1 mM MBT was observed for Ag metal etched for 30 s in NH₄OH followed by 10 s in HNO₃. Further, MBT could be quantified with detection limits of 1 pM and 100 µM, respectively, using 514 nm and 1064 nm Raman spectrometers. Thus, a rapid and less energy intensive method for producing solid Ag SERS substrate and its efficacy in analyte sensing was demonstrated.
authors: Biomedical Engineering Theme, Institute for Environment, Health and Societies, Brunel University London, Uxbridge UB8 3PH, UK. shav1988@gmail.com.|Department of Mechanical, Aerospace and Civil Engineering, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK. shav1988@gmail.com.
authors: Shavini
authors: S
authors: Wijesuriya
authors: Biomedical Engineering Theme, Institute for Environment, Health and Societies, Brunel University London, Uxbridge UB8 3PH, UK. krishna.burugapalli@brunel.ac.uk.|Department of Mechanical, Aerospace and Civil Engineering, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK. krishna.burugapalli@brunel.ac.uk.
authors: Krishna
authors: K
authors: Burugapalli
authors: Biomedical Engineering Theme, Institute for Environment, Health and Societies, Brunel University London, Uxbridge UB8 3PH, UK. Ruth.MacKay@brunel.ac.uk.|Department of Mechanical, Aerospace and Civil Engineering, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK. Ruth.MacKay@brunel.ac.uk.
authors: Ruth
authors: R
authors: Mackay
authors: Department of Mechanical, Aerospace and Civil Engineering, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK. gi14gga@my.brunel.ac.uk.
authors: Godwin Chukwuebuka
authors: GC
authors: Ajaezi
authors: Biomedical Engineering Theme, Institute for Environment, Health and Societies, Brunel University London, Uxbridge UB8 3PH, UK. Wamadeva.Balachandran@brunel.ac.uk.|Department of Electronic and Computer Engineering, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK. Wamadeva.Balachandran@brunel.ac.uk.
authors: Wamadeva
authors: W
authors: Balachandran
keywords: 514 nm and 1064 nm Raman; SERS substrate; chemical etching; solid silver; surface roughness