Aluminum Film-Over-Nanosphere Substrates for Deep-UV Surface- Enhanced Resonance Raman Spectroscopy

Bhavya Sharma,‡,† M. Fernanda Cardinal,† Michael B. Ross,† Alyssa B. Zrimsek,† Sergei V. Bykov,§ David Punihaole,§ Sanford A. Asher,§ George C. Schatz,† and Richard P. Van Duyne*,†
†Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
‡Department of Chemistry, University of Tennessee, 1420 Circle Drive, Knoxville, Tennessee 37996, United States
§Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States

ABSTRACT: We report here the first fabrication of aluminum film-over nanosphere (AlFON) substrates for UV surface-enhanced resonance Raman scattering (UVSERRS) at the deepest UV wavelength used to date (λex = 229 nm). We characterize the AlFONs fabricated with two different support microsphere sizes using localized surface plasmon resonance spectroscopy, electron microscopy, SERRS of adenine, tris-(bipyridine)ruthenium(II), and trans-1,2-bis(4-pyridyl)-ethyl-ene, SERS of 6-mercapto-1-hexanol (as a nonresonant molecule), and dielectric function analysis. We find that AlFONs fabricated with the 210 nm microspheres generate an enhancement factor of approximately 104−5, which combined with resonance enhancement of the adsorbates provides enhancement factors greater than 106. These experimental results are supported by theoretical analysis of the dielectric function. Hence our results demonstrate the advantages of using AlFON substrates for deep UVSERRS enhancement and contribute to broadening the SERS application range with tunable and affordable substrates.
© 2016 American Chemical Society
Aluminum Film-Over-Nanosphere Substrates for DUV SERRS 2016