Electrochemically etched pores and wires on smooth and textured GaAs surfaces

► Triangular GaAs nanowires were observed at low potentials while pronounced lateral etching occurred at high potentials. ► A pore growth direction was changed from 〈1 1 1〉B to 〈0 0 1〉 at a high current density. ► Tetrahedron-like pores along 〈1 1 1〉B transformed into 200 μm-deep pores along the 〈0 0 1〉 direction.