Triangular GaAs Microcones and Sharp Tips Prepared by Combining Electroless and Electrochemical Etching

Abstract

We developed a method for making triangular GaAs microcones with sharp tips by combining electroless and electrochemical etching. Silver nanoparticles were first uniformly distributed by electroless plating and were subsequently used as catalysts for generating a uniform shallow textured surface during chemical etching. The pretextured surface provided pore nucleation sites, allowing for easier further electrochemical etching with good uniformity. Adding H2O2 into the electrolyte caused pore widening with crystallographically oriented etching, which then resulted in GaAs microcones and sharp tips. The direction of pore growth was also observed to change from < 111 > B to < 111 > A at a high potential. Cone and sharp tip arrays prepared using this approach may have potential applications for photovoltaic and field-emission devices based upon III- V compounds. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3244592] All rights reserved.