title: Demonstration of surface-enhanced Raman scattering by tunable, plasmonic gallium nanoparticles.
abstract: Size-controlled gallium nanoparticles deposited on sapphire were explored as alternative substrates to enhance Raman spectral signatures. Gallium's resilience following oxidation is inherently advantageous in comparison with silver for practical ex vacuo nonsolution applications. Ga nanoparticles were grown using a simple molecular beam epitaxy-based fabrication protocol, and monitoring their corresponding surface plasmon resonance energy through in situ spectroscopic ellipsometry allowed the nanoparticles to be easily controlled for size. The Raman spectra obtained from cresyl fast violet (CFV) deposited on substrates with differing mean nanoparticle sizes represent the first demonstration of enhanced Raman signals from reproducibly tunable self-assembled Ga nanoparticles. Nonoptimized aggregate enhancement factors of approximately 80 were observed from the substrate with the smallest Ga nanoparticles for CFV dye solutions down to a dilution of 10 ppm.
authors: Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA. pae.wu@duke.edu
authors: Pae C
authors: PC
authors: Wu
authors: Christopher G
authors: CG
authors: Khoury
authors: Tong-Ho
authors: TH
authors: Kim
authors: Yang
authors: Y
authors: Yang
authors: Maria
authors: M
authors: Losurdo
authors: Giuseppe V
authors: GV
authors: Bianco
authors: Tuan
authors: T
authors: Vo-Dinh
authors: April S
authors: AS
authors: Brown
authors: Henry O
authors: HO
authors: Everitt
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D005708:Gallium / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties; D013696:Temperature
chemical_list: D005708:Gallium; D000537:Aluminum Oxide