Photonic crystal nanocavities in GaAs/AlGaAs with oxidised bottom cladding

Karl Welna*, Maxime Hugues, Christopher P. Reardon, Liam O'Faolain, Mark Hopkinson, Thomas F. Krauss

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


We present a solution to the difficult task of removing an oxide-based hard mask from a photonic crystal fabricated in the GaAs/ AlGaAs system. We use a polymer backfill technique to seal the AlGaAs layer, thereby making it inaccessible to the wet-etch solution. This allows us to use a GaAs active layer for the photonic crystal placed on an oxidised AlGaAs layer which provides mechanical and thermal support. Using this technique, we fabricated GaAs-based photonic crystal cavities and measured respectable quality factors (Q approximate to 2200) despite the intrinsic asymmetry of the system. The technique presents a viable method for producing electrically injected photonic crystal cavities for operation on a mechanically stable and thermally conducting buffer layer. (C) 2013 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)139-144
Number of pages6
JournalPhotonics and Nanostructures : Fundamentals and Applications
Issue number2
Early online date20 Dec 2012
Publication statusPublished - May 2013


  • Photonic crystal
  • Cavity
  • Oxide
  • Fabrication
  • Hard mask
  • Oxidation
  • Backfill
  • Wave guides
  • Lasers
  • Operation


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