文摘
A model metal鈥搒emiconductor鈥搈olecule鈥搈etal assembly has been designed for probing the charge-transfer (CT) mechanism of surface-enhanced Raman scattering (SERS). We measured the SERS of ZnO鈥揚ATP鈥揂g, Au鈥揨nO鈥揚ATP鈥揂g, and Cu鈥揨nO鈥揚ATP鈥揂g assemblies at excitation wavelengths of 514.5, 785, and 1064 nm. Our results demonstrate that the metal鈥搒emiconductor contact can alter the charge distribution through p-aminothiophenol (PATP) molecules. This is attributed to the chemical SERS enhancement mechanism with additional electrical transport properties within these assemblies. These inhibit the CT from the metal to the molecule, resulting in the different degrees to which CT contributes to the overall SERS enhancement of PATP.