Figure 23.2 — Photoluminescence of nanowires Figure 23.2 — Photoluminescence of nanowires. (a) Cross-section of a SEM image of silicon nanowires obtained by the metal-assisted wet etching technique. Image credits: Alessia Irrera. (b) Photoluminescence spectra obtained by exciting silicon nanowire samples having different diameters with 488 nm light. The blue shift for smaller diameters indicates stronger quantum confinement.Reproduced with permission from Irrera et al., Nanotechnol. 23, 075204. Copyright (2012) IOP Publishing. Reproduced by permission of IOP Publishing. All rights reserved.