It might look like Manhattan or Chicago, but this cityscape is actually formed from the world’s first synthetic “nanocolumns”. Towering between two and five micrometres above a sapphire base, each “skyscraper” is a column of stacked zinc oxide crystals. Single hexagonal crystals form each “storey”, gradually diminishing in diameter with height.
Yunqi Liu and his team at the Chinese Academy of Sciences’ Institute of Chemistry in Beijing made the towers in a furnace by reacting zinc sulphide with oxygen at 950 °C. Zinc oxide is a semiconductor that serves a variety of functions in conductive films and electronic transducers. The…
