Etching Morphology of Single-Crystal Copper

A copper (100) single crystal forms a square etched morphology, with the sides of the square consisting of several macro steps expanding along the (100) plane. A copper (110) single crystal forms a triangular columnar morphology. Because the bottom plane is (110), the four other planes of the morphology should be (100). A copper (111) single crystal forms a triangular pyramidal morphology. The bottom plane is (111), so the three other sides should be (100) planes. The etched morphology of (100), (110), and (111) single-crystal copper may be explained on the basis of etching of the (100) plane.