Controlled Etching Behavior of O-Polar and Zn-Polar ZnO Single Crystals

Abstract

We report on optimized wet chemical processes for both the O-polar and Zn-polar faces of wurtzite bulk ZnO single crystals. Different solutions were tested to achieve controllable etching. For the O-polar ZnO surface, a controlled etch rate of was observed using an acid mixture of as an etchant. Fine-patterning of the O-polar surface with moderate etch rates and high reproducibility can be obtained using an aqueous 5% solution. In comparison, the Zn-polar ZnO surface etches significantly slower in HCl solution and exhibits strong dependence. Nevertheless, control enables reproducible etching even of the Zn-polar surface.