High-sensitivity humidity sensor based on a single SnO2 nanowire

building blocks for constructing nanosized devices due to high surface to volume ratio and their special physical and chemical properties resulting from the reduced sizes. Until now, many semiconductor NWs/NBs have been successfully applied in nan-odevices, including nanolasers,1 nanogenerators,2 and various chemical and biological nanosensors.3,4 Well-known humidity control is very important for many fields in technology and our daily life. In the past years, many detection techniques have been explored from old wet and dry bulb thermometry to modern capacitive, resistive, and thermal conductive moisture detectors. In order to further promote the sensitivity, selectivity, chemical and thermal stability, intensive efforts have been put in the exploration of a humidity sensor based on nanostructured materials such as carbon nanotubes,5 metal oxide nanoparticles,6 and NW films.