title: High-Resolution Distance Dependence Study of Surface-Enhanced Raman Scattering Enabled by Atomic Layer Deposition.
abstract: We present a high-resolution distance dependence study of surface-enhanced Raman scattering (SERS) enabled by atomic layer deposition (ALD) at 55 and 100 °C. ALD is used to deposit monolayers of Al2O3 on bare silver film over nanospheres (AgFONs) and AgFONs functionalized with self-assembled monolayers. Operando SERS is used to measure the intensities of the Al-CH3 and C-H stretches from trimethylaluminum (TMA) as a function of distance from the AgFON surface. This study clearly demonstrates that SERS on AgFON substrates displays both a short- and long-range nanometer scale distance dependence. Excellent agreement is obtained between these experiments and theory that incorporates both short-range and long-range terms. This is a high-resolution operando SERS distance dependence study performed in one integrated experiment using ALD Al2O3 as the spacer layer and Raman label simultaneously. The long-range SERS distance dependence should make it possible to detect chemisorbed surface species located as far as ∼3 nm from the AgFON substrate and will provide new insight into the surface chemistry of ALD and catalytic reactions.
authors.affiliation: Department of Chemistry and ‡Center for Catalysis and Surface Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Sicelo S
authors.initials: SS
authors.lastname: Masango
authors.affiliation: Department of Chemistry and ‡Center for Catalysis and Surface Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Hackler
authors.affiliation: Department of Chemistry and ‡Center for Catalysis and Surface Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Large
authors.affiliation: Department of Chemistry and ‡Center for Catalysis and Surface Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Anne-Isabelle
authors.initials: AI
authors.lastname: Henry
authors.affiliation: Department of Chemistry and ‡Center for Catalysis and Surface Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Michael O
authors.initials: MO
authors.lastname: McAnally
authors.affiliation: Department of Chemistry and ‡Center for Catalysis and Surface Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: George C
authors.initials: GC
authors.lastname: Schatz
authors.affiliation: Department of Chemistry and ‡Center for Catalysis and Surface Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Stair
authors.affiliation: Department of Chemistry and ‡Center for Catalysis and Surface Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Van Duyne
keywords: Surface-enhanced Raman scattering; atomic layer deposition; distance dependence; operando