Fig. 5
From: Subwavelength core/shell cylindrical nanostructures for novel plasmonic and metamaterial devices
(a–c are adapted from [35] and d–g are adapted from [36])
Strong enhancement of luminescence and quantum efficiency of NWs coupled to plasmonic nanocavities. a Schematic illustration of a Si NW coupled to an Ω-shaped Ag plasmonic nanocavity device for visible hot luminescence (top). Optical microscopy images of the fabricated single plasmonic NW device (bottom, left) and its hot luminescence recorded under focused laser excitation (bottom, right). b Photoluminescence spectra of a bare Si NW (blue) and a Si NW coupled to an Ω-shaped plasmonic nanocavity (magenta) at room temperature. c Calculated electric field intensity profiles of various plasmonic modes excited in the NW plasmonic nanocavity. The diameter of Si NW is 70 nm. d Schematic illustration of a III–V NW coupled to an Ω-shaped Au plasmonic nanocavity to achieve high quantum efficiency. e SEM images of a core/shell/cap GaAs/AlGaAs/GaAs NW showing diameter variations along the NW length. f Measured photoluminescence spectra of a bare GaAs/AlGaAs/GaAs core/shell/cap NW (red) and a NW coupled to an Ω-shaped plasmonic nanocavity (blue). g Time-resolved photoluminescence data obtained from the bare and nanocavity-coupled NWs. The estimated minority carrier lifetimes are 1.5 and 0.5 ns for the bare and nanocavity-coupled NWs, respectively