Influence of Atomic Hydrogen, Band Bending, and Defects in the Top Few Nanometers of Hydrothermally Prepared Zinc Oxide Nanorods

Mubarak J. Al-Saadi, Salim H. Al-Harthi*, Htet H. Kyaw, Myo T Z Myint, Tanujjal Bora, Karthik Laxman, Ashraf Al-Hinai, Joydeep Dutta

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

We report on the surface, sub-surface (top few nanometers) and bulk properties of hydrothermally grown zinc oxide (ZnO) nanorods (NRs) prior to and after hydrogen treatment. Upon treating with atomic hydrogen (H*), upward and downward band bending is observed depending on the availability of molecular H2O within the structure of the NRs. In the absence of H2O, the H* treatment demonstrated a cleaning effect of the nanorods, leading to a 0.51 eV upward band bending. In addition, enhancement in the intensity of room temperature photoluminescence (PL) signals due to the creation of new surface defects could be observed. The defects enhanced the visible light activity of the ZnO NRs which were subsequently used to photocatalytically degrade aqueous phenol under simulated sunlight. On the contrary, in the presence of H2O, H* treatment created an electronic accumulation layer inducing downward band bending of 0.45 eV (~1/7th of the bulk ZnO band gap) along with the weakening of the defect signals as observed from room temperature photoluminescence spectra. The results suggest a plausible way of tailoring the band bending and defects of the ZnO NRs through control of H2O/H* species.

Original languageEnglish
Article number22
JournalNanoscale Research Letters
Volume12
Issue number1
DOIs
Publication statusPublished - Dec 1 2017

Keywords

  • Band bending
  • Hydrogen treatment
  • Surface defects
  • Visible light photocatalysis
  • ZnO

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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