Charge-selective Raman scattering and fluorescence quenching by "nanometal on semiconductor" substrates.

Bhatt, Karthik; Tan, Susheng; Karumuri, Sriharsha; Kalkan, A Kaan · Nano Lett · 2010

basic_science · Level V

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Abstract

Ag nanoparticles synthesized on n and p-type Si were shown to exhibit charge-selective surface-enhanced Raman scattering and fluorescence quenching. As revealed by electric force microscopy, the polarity and magnitude of the nanoparticle charge is controllable with the metal-semiconductor Fermi level difference and nanoparticle size. It is inferred that the Fermi level alignment is dominantly contributed by the charge-induced nanoparticle voltage. Nanoparticle charging also accounts for self-inhibition of coalescence during chemical reduction, allowing strong plasmon hybridization.