Dislocations as channels for the fabrication of sub-surface porous GaN by electrochemical etching

Fabien C.-P. Massabuau, Peter H. Griffin, Helen P. Springbett, Yingjun Liu, R. Vasant Kumar, Tongtong Zhu, Rachel A. Oliver

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)
16 Downloads (Pure)


Porosification of nitride semiconductors provides a new paradigm for advanced engineering of the properties of optoelectronic materials. Electrochemical etching creates porosity in doped layers whilst leaving undoped layers undamaged, allowing the realisation of complex three-dimensional porous nanostructures, potentially offering a wide range of functionalities, such as in distributed Bragg reflectors. Porous/non-porous multilayers can be formed by etching whole, as-grown wafers uniformly in one simple process, without any additional processing steps. The etch penetrates from the top down, through the undoped layers, leaving them almost untouched. Here, atomic-resolution electron microscopy is used to show that the etchant accesses the doped layers via nanometre-scale channels that form at dislocation cores and transport the etchant and etch products to and from the doped layer respectively. Results on AlGaN and non-polar GaN multilayers indicate the same mechanism is operating, suggesting this approach may be applicable in a range of materials.
Original languageEnglish
Article number031115
Number of pages14
JournalAPL Materials
Issue number3
Early online date25 Mar 2020
Publication statusPublished - 30 Mar 2020


  • electrochemical etching
  • porous nanostructures
  • electron microscopy


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