The light–matter interaction of a single semiconducting AlGaN nanowire and noble metal Au nanoparticles in the sub-diffraction limit

Abstract

Near field scanning optical microscopy (NSOM) is not only a tool for imaging of sub-diffraction limited objects but also a prominent characteristic tool for understanding the intrinsic properties of nanostructures. In order to understand light–matter interactions in the near field regime using a NSOM technique with an excitation of 532 nm (2.33 eV), we selected an isolated single semiconducting AlGaN nanowire (NW) of diameter ∼120 nm grown via a vapor liquid solid (VLS) mechanism along with a metallic Au nanoparticle (NP) catalyst. The role of electronic transitions from different native defect related energy states of AlGaN is discussed in understanding the NSOM images for the semiconducting NW. The effect of strong surface plasmon resonance absorption of an excitation laser on the NSOM images for Au NPs, involved in the VLS growth mechanism of NWs, is also observed.