Mechanistic characteristics of metal-assisted chemical etching in GaAs

Ho Yuen Cheung, Hao Lin, Fei Xiu, Fengyun Wang, Senpo Yip, Johnny C. Ho, Chun Yuen Wong

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


Because of the unique physical properties, various GaAs micro-and nanostructures have attracted increasing research attention for many technical applications such as solar cells, light-emitting diodes, and field-effect transistors. In this regard, numerous fabrication techniques have been explored, and among all, metal-assisted chemical etching is successfully applied to GaAs in order to achieve cost-effective, large-scale, and complex structures. However, the detailed explanations as well as the corresponding etching mechanism have not been reported until now or simply relied on the hole injection model of Si in order to explain the phenomenon. In this work, we perform a more systematic study to further explore and assess the etching phenomenon of GaAs employing the Au catalyst and the [KMnO4/H 2SO4] etch system. It is revealed that the anisotropic etching behavior of GaAs is predominantly due to the Au-induced surface defects at the Au/GaAs interface, which makes the particular area more prone to oxidation and thus results in the simple directional wet etching; for that reason, more anisotropic etch is obtained for the Au pattern with higher edge-to-surface-area ratio. All these findings not only offer additional insight into the MacEtch process of GaAs but also provide essential information on different etching parameters in manipulating this anisotropic wet etching to achieve the fabrication of complex GaAs structures for technological applications.

Original languageEnglish
Pages (from-to)6903-6908
Number of pages6
JournalJournal of Physical Chemistry C
Issue number13
Publication statusPublished - Apr 3 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films


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