Fabrication of ZnO Microstructures by Anisotropic Wet-Chemical Etching

Abstract

ZnO microstructures were fabricated by wet-chemical etching with aqueous solutions of HCl and and patterned resist masks prepared by electron-beam lithography. Anisotropy of the etching rate caused the formation of microstructures corresponding to the crystal habit. In fact, all the pit structures made on , , and surfaces of ZnO single crystal were characterized by {} faces, and all the pyramidal structures made on the surface were characterized by {} facets forming hexagonal projections. Regarding etchant dependence, enabled us to create structures with sharp edges and corners, while etching with HCl[aq] resulted in structures with rounded shapes. The coalescence of pits during chemical etching was also investigated using mask patterns having symmetrically aligned windows that were close to each other.