About the Interaction Between a Laser Beam and Group Ⅳ Nanowires: A Study of the Electromagnetic Field Enhancement in Homogeneous and Heterostructured Nanowires

摘要

The optical properties of semiconductor nanowires (NWs) are object of studybecause they are the building blocks of the future nanophotonic devices. Thehigh refractive index and its reduced dimension, make them suitable forphoton engineering. The study of the interaction between NWs and visiblelight has revealed resonances of the light absorption/scattering by the NWs.Micro-Raman spectroscopy is used as a characterization method of semiconductorNWs. The relation between the Raman intensity and the incidentelectromagnetic (EM) field permits to study the light/NW interaction throughthe micro-Raman spectra of individual NWs. As compared to either metallicor dielectric NWs, the semiconductor NWs add additional tools to modify itsinteraction with light, for example, the composition, the presence ofheterostructures, both axial and radial, doping, and the surface morphology.One presents herein a study of the optical response of group Ⅳ semiconductorNWs to visible photons. The study is experimentally carried out throughthe micro-Raman spectroscopy of different group IV NWs, both homogeneousand heterostructured (SiGe/Si), and the results are analyzed in termsof the EM modeling of the light/NW interaction using finite element methods(FEMs). The heterostructures are seen to produce additional resonancesallowing new photonic capacities to the semiconductor NWs.