Metal−Molecule Schottky Junction Effects in Surface Enhanced Raman Scattering

Abstract

We propose a complementary interpretation of the mechanism responsible for the strong enhancement observed in Surface Enhanced Raman Scattering (SERS). The effect of a strong static local electric field due to Schottky barrier at the metal-molecule junction on SERS is systematically investigated. The study provides a viable explanation to the low repeatability of SERS experiments as well as the Raman peak shifts as observed in SERS and raw Raman spectra. It was found that strong electrostatic build-in field at the metal-molecule junction along specific orientations can result in 2-4 more orders of enhancement in SERS.

Laser fabricated ripple substrates for surface‐enhanced Raman scattering

“…The SERS ripple enhancement is 6 times higher for Ag coating at 633 nm excitation, as expected since local optical field enhancement is higher for silver nanoparticles [25,28]. Also, it is noteworthy that thiophenol exhibits metal-adsorbate induced states that become resonant at different excitation wavelengths, depending on the metal [22,30,31]. The ripple SERS enhancement is increasing for longer wavelengths as tested with Ag coating (Fig.…”

Highly crystalline ZnO film decorated with gold nanospheres for PIERS chemical sensing

“…Here, a charge transfer mechanism from the Fermi level of AuNP to the lowest unoccupied molecular orbital (LUMO) level of thiophenol molecule (see Fig.2b) has occurred and enabled by the red laser (λ exc = 633 nm; energy = 1.96 eV), thus enhancing the Raman signal (called charge-transfer resonance Raman enhancement) 25 . The ionization potentials are 7.71 eV 26 and 8.32 eV 27 for ZnO and thiophenol, respectively, and the gap energies associated to ZnO and thiophenol are 3.37 eV 13 and 4.09 eV 27 , respectively. The work function (W) of gold is 5.1 eV 28 .…”

Capturing Irradiation with Nanoantennae: Plasmon‐Induced Enhancement of Photoelectrolysis

“…The signal observed from the CE depends on the charge transfer mechanism and leads to enhancement factors of 10 2 -10 4 . Experimental as well as theoretical studies have, however, suggested that the EF could be actually much larger 45,46 . Two main processes have been suggested for possible SERS charge transfer: the first (cf.…”