Direct growth of self-aligned single-crystalline GaN nanorod array on flexible Ta foil for photocatalytic solar water-splitting

Prashant Tyagi, Ch Ramesh, Jyoti Kaswan, Swati Dhua, Subish John, Ajay Kumar Shukla, Somnath C. Roy, Sunil Singh Kushvaha, Senthil Kumar Muthusamy

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

We report the direct growth of self-aligned single crystalline GaN nanorod array on flexible Ta metal foil using laser molecular beam epitaxy. Scanning electron microscopy reveals the vertically aligned nanorods on Ta surface having diameters in the range of 60–80 nm. The nanorods show well-defined hexagonal facets and are quite uniformly distributed across the metal foil. Transmission electron microscopy shows single crystalline nature of the individual rods having c-axis oriented growth with wurtzite structure. Room temperature photoluminescence study exhibits a sharp, intense band-to-band emission without any deep-level bands indicating the excellent optical quality of the GaN nanorod array. X-ray photoemission spectroscopy to elucidate the electronic structure of the nanorods confirms Ga–N bonding and the calculated chemical composition turns out to be slightly Ga rich. Location of valence band maxima also suggests the n-type character of GaN nanorods. The photoelectrochemical water-splitting behaviour of the self-aligned GaN nanorod arrays on Ta foil has been investigated using 1 M oxalic acid as the electrolyte with AM 1.5 G simulated solar radiation under 1 Sun (100 mW/cm2) conditions. The results demonstrate an effective way of fabricating well-aligned GaN nanorods on flexible metal foils for developing simple, relatively inexpensive, and flexible photo-electrodes for photocatalytic solar water-splitting applications.

Original languageEnglish
Pages (from-to)97-103
Number of pages7
JournalJournal of Alloys and Compounds
Volume805
DOIs
StatePublished - 15 Oct 2019
Externally publishedYes

Keywords

  • Epitaxial growth
  • GaN
  • Metal foil
  • Nanorod
  • Water-splitting

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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