Figure 1. Hot-luminescence from silicon coupled to a plasmon nanocavity.

a, Schematic of the electronic band diagram of bulk crystalline silicon illustrating phonon-assisted hot-luminescence processes before the thermalization of the carriers to the minimum of the conduction band near the X-point. b, Schematic of an Ω-shaped plasmonic nanocavity coupled silicon nanowire device. c, Scanning electron microscope (SEM) image of the fabricated device. d and e, Optical images of a single-plasmonic silicon nanowire device obtained through the glass substrate under white light (d), and a focused laser excitation (e). f, Room-temperature photoluminescence spectra from single silicon nanowire device coupled with Ω-shaped (magenta) cavity (100 nm Ag film) having the silicon nanowire diameter, d, of 65 nm. Spectrum of a 5 nm SiO₂ coated single silicon nanowire without a plasmonic cavity (blue; d = 60 nm) is also shown, with no observable photon counts without the plasmonic cavity.