Nanopropeller arrays of zinc oxide

Polar surface dominated ZnO nanopropeller arrays were synthesized by a two-step high temperature solid-vapor deposition process. The axis of the nanopropellers is a straight nanowire along the c axis and enclosed by {21̄1̄0} surfaces, which grew first; the sixfold symmetric nanoblades are later formed along the crystallographic equivalent a axes (〈21̄1̄0〉) perpendicular to the nanowire; and the array is formed by epitaxial growth of nanoblades on the nanowire. The top surface of the nanoblade is the Zn terminated +c plane, showing surface steps and possible secondary growth of nanowires due to higher self-catalytic activity, while the back surface is the oxygen-terminated −c plane, which is smooth and inert.