Stable and Reversible Photoluminescence from GaN Nanowires in Solution Tuning by Ionic Concentration

Anh Thi Nguyen, Ya Wen Ho, Wei Cheng Yu, Hsiao-Wen Zan, Hsin-Fei Meng*, Yi-Chia Chou

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We report response of photoluminescence (PL) from GaN nanowires without protection in solutions. The distinct response is not only toward pH but toward ionic concentration under same pH. The nanowires appear to be highly stable under aqueous solution with high ionic concentration and low pH value down to 1. We show that the PL has a reversible interaction with various types of acidic and salt solutions. The quantum states of nanowires are exposed to the external environment and have a direct physical interaction which depends on the anions of the acids. As the ionic concentration increases, the PL intensity goes up or down depending on the chemical species. The response results from a competition of change in surface band bending and charge transfer to redox level in solution. That of GaN films is reported for comparison as the effect of surface band bending can be neglected so that there are only slight variations in PL intensity for GaN films. Additionally, such physical interaction does not impact on the PL peaks in acids and salts, whereas there is a red shift on PL when the nanowires are in basic solution, say NH4OH, due to chemical etching occurred on the nanowires.

Original languageEnglish
Article number45
Pages (from-to)1-9
Number of pages9
JournalNanoscale Research Letters
Issue number1
StatePublished - 11 Mar 2021


  • GaN nanowires
  • Ionic concentration
  • Photoluminescence response
  • Physical interaction
  • Reversibility


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