Mass production and characterization of free-standing ZnO nanotripods by thermal chemical vapor deposition

Mass-productive free-standing ZnO nanotripods were obtained by thermal chemical vapor deposition without introduction of catalysts and substrates. Three arms of ZnO nanotripods had lengths ranging from 300 nm to 1.0 μm and a single-crystalline hexagonal structure. It was found that an inverted triangle-shaped zinc blende ZnO core is located at the center of the grown ZnO nanotripod and a twin structure exists at the interface between each arm. The three arms with extremely narrow diameters below 20 nm were grown along to the [0 0 0 1] c-axis and the twin boundary was identified as (0 1 1̄ 3). ZnO nanotripods exhibited a relatively weak deep-level emission band as well as strong near band-edge emission in the room-temperature photoluminescence measurement, indicating the high optical quality and low defect density of the ZnO nanotripods.