O nanotree, O nanotree ... how small are your leaves

Happy Christmas from Dr. Jiushuai Xu and Professor Erwin Peiner! They fabricated probably the world’s tiniest Christmas trees by growing zinc oxide nanowires on silicon nanowires. The “nano Christmas tree” is so small, it needs a scanning electron microscope to be marvelled at.

Probably the world’s tiniest Christmas tree. Picture credits: IHT/TU Braunschweig

In contrast to its macroscopic counterparts, the nano-tree has also practical use. The nanowires have shown great promise for the next generation of smart bio- and chemical sensors, energy harvesters (for example photovoltaics and thermoelectrics) and storage (lithium-ion batteries or supercapacitors, for example). For instance, the scientists from TU Braunschweig’s Institute of Semiconductor Technology have successfully utilised nanowires as microsensors, realizing the detection of the toxic gas nitrogen dioxide on part per billion level.