Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5460825 | Journal of Alloys and Compounds | 2017 | 16 Pages |
Abstract
The objective of this work is to obtain a strong and a broad visible surface plasmon resonance (SPR) and also to tune the wavelength towards red region in thermally evaporated bimetal Ag-Cu film which will act as relatively sensitive surface enhanced Raman spectroscopy (SERS) substrate for the application in bio molecule detection. For the optimization, the morphological property including surface roughness, number-particle density, size distribution and inter-particle distances were altered through varying Cu content in Ag-Cu and temperature by vacuum thermal annealing. The effective dielectric constant of Ag-Cu films is studied from theoretical simulation using extended Maxwell garnet method demonstrating a strong plasmonic character as compared to pure Ag and Cu films. The elemental composition and the surface oxidation states of Ag-Cu film are probed through X-ray photoelectron spectroscopy (XPS). SERS study of RhG molecules exhibit higher enhancement factor for Ag0.75Cu0.25 film (annealed at 100 °C) as compared to pure Ag and Cu by the factor of 1.6 and 50 respectively and congruently the limit of detection was found to be 10â9 M. The higher SERS homogeneity with the least standard deviation of 18% on RhG molecules was studied through Raman mapping and bar plot. A broad and visible SPR band optimized towards red region on Ag0.75Cu0.25film may improve the sensitivity of bio-molecules detection.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Anil Kumar Pal, D. Bharathi Mohan,