Surface-Passivated AlGaN Nanowires for Enhanced Luminescence of Ultraviolet Light Emitting Diodes

Haiding Sun, Mohammad Khaled Shakfa, Mufasila Mumthaz Muhammed, Bilal Janjua, Kuang Hui Li, Ronghui Lin, Tien Khee Ng, Iman S. Roqan, Boon S. Ooi, Xiaohang Li*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

66 Scopus citations

Abstract

Spontaneously grown, self-aligned AlGaN nanowire ultraviolet light emitting diodes still suffer from low efficiency partially because of the strong surface recombination caused by surface states, i.e., oxidized surface and high-density surface states. Several surface passivation methods have been introduced to reduce surface nonradiative recombination by using complex and toxic chemicals. Here, we present an effective method to suppress such undesirable surface recombination of the AlGaN nanowires via diluted potassium hydroxide (KOH) solution, a commonly used chemical process in semiconductor fabrication that is barely used as surface passivation solution in self-assembled nitride-based nanowires. The transmission electron microscopy investigation on the samples reveals almost intact nanowire structures after the passivation process. We demonstrated an approximately 49.7% enhancement in the ultraviolet light output power after a 30 s KOH treatment on AlGaN nanowires grown on titanium-coated silicon substrates. We attribute such a remarkable enhancement to the removal of the surface dangling bonds and oxidized nitrides (Ga-O or Al-O bonds) at the surface as we observe the change of the carrier lifetime before and after the passivation. Thus, our results highlight the possibility of employing this process for the realization of high-performance nanowire UV emitters.

Original languageEnglish (US)
Pages (from-to)964-970
Number of pages7
JournalACS PHOTONICS
Volume5
Issue number3
DOIs
StatePublished - Mar 21 2018

Keywords

  • Aluminum gallium nitride nanowire
  • passivation
  • potassium hydroxide
  • surface oxides and states
  • surface recombination
  • ultraviolet light emitting diode

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering
  • Biotechnology

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