In-plane and out-of-plane mass transport during metal-assisted chemical etching of GaAs

Abstract

We have demonstrated the dependence of the metal-assisted chemical etching of GaAs on catalyst thickness. For ultra-thin (3~10 nm) Au catalysts, we found that electrochemically generated nano-pinholes in the metal catalyst not only enhance important catalytic effects in redox reactions, but also act as a diffusion pathway for the reactants (H₂SO₄) and products (Ga³⁺ and Asⁿ⁺ ions) for chemical etching oxidized GaAs.