Fig. 7
From: Stable and Reversible Photoluminescence from GaN Nanowires in Solution Tuning by Ionic Concentration
The PL spectra of GaN nanowires in NH4OH and the corresponding SEM images. a Signals when nanowires are in NH4OH at pH = 11.24. b Signals when nanowires are in NH4OH at pH = 14.02. c SEM image of the as-grown GaN nanowires. d The GaN nanowires after immersing in NH4OH solution for 20 min. e SEM image of the as-grown GaN nanowires. f The nanowires after the tests of immersing them into the acidic solution, HCl, for 20 min