Simultaneous growth strategy of high-optical efficiency GaN NWs on a wide-range of substrates by pulsed laser deposition

Dhaifallah Almalawi, Sergei Lopatin, Paul R. Edwards, Bin Xin, Ram C. Subedi, Mohammed A. Najmi, Fatimah Alreshidi, Alessandro Genovese, Daisuke Iida, Nimer Wehbe, Boon S. Ooi, Kazuhiro Ohkawa, Robert W. Martin, Iman S. Roqan

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Here, we explore a catalyst-free single-step growth strategy that results in high-quality self-assembled single-crystal vertical GaN nanowires (NWs) grown on a wide range of common and novel substrates (including GaN, Ga 2O 3, and monolayer two-dimensional (2D) transition-metal dichalcogenide (TMD)) within the same chamber and thus under identical conditions by pulsed laser deposition. High-resolution transmission electron microscopy and scanning transmission electron microscopy (HR-STEM) and grazing incidence X-ray diffraction measurements confirm the single-crystalline nature of the obtained NWs, whereas advanced optical and cathodoluminescence measurements provide evidence of their high optical quality. Further analyses reveal that the growth is initiated by an in situ polycrystalline layer formed between the NWs and substrates during growth, while as its thickness increases, the growth mode transforms into single-crystalline NW nucleation. HR-STEM and corresponding energy-dispersive X-ray compositional analyses indicate possible growth mechanisms. All samples exhibit strong band edge UV emission (with a negligible defect band) dominated by radiative recombination with a high optical efficiency (∼65%). As all NWs have similar structural and optical qualities irrespective of the substrate used, this strategy will open new horizons for developing III-nitride-based devices.

Original languageEnglish
Pages (from-to)46804-46815
Number of pages12
JournalACS Omega
Issue number49
Early online date1 Dec 2023
Publication statusPublished - 12 Dec 2023


  • III-nitrides
  • catalyst-free single-crystal nanowires
  • 2D substrate
  • polycrystalline buffer
  • affordable and emerging substrates


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