The localized surface plasmon resonance on noble metal-semiconductor: Au nanosphere-ZnO nanorod

Abstract

In this work, we have investigated the localized surface plasmon resonance of metal-semiconductor model. The raw materials are gold nanosphere (Au-NP) and ZnO nanorod (ZnO-NR). The nanoparticles were surrounded by air with refractive index constant (1.0+0i). Moreover, the diameter and aspect ratio of Au-NP and ZnO-NR were 40 nm and 4, respectively. Then, we designed the nanoparticle in two different configurations. First, Au-NP was placed at the sides of ZnO-NR and second, Au-NP was placed at the tip of nanorod. Next, we varied the gap-distance among them from 0 nm to 40 nm with 10 nm increment. The photon wavelength used were from 300 nm to 1200 nm within two different excitations (transverse and longitudinal excitation). Furthermore, our result suggests that on the longitudinal excitation, when the gap-distance increases, the resonance peak of second configuration remains at constant value and the intensity significantly decreases compared to the first configuration. However, on the transverse excitation, the first configuration has a high intensity and the resonance peaks is slightly red-shifted. In addition, based on the near-field mapping which reflects the energy density of electromagnetic field by LSPR, the LSPR of Au-NP stands to aid the exciton production to enhance the photocatalytic activity.