ZnSe nanorods prepared in hydroxide-melts and their application as a humidity sensor

We have synthesized the crystalline ZnSe nanorods for the first time using the molten hydroxides as reaction solvent in the absence of organic dispersant or capping agents. The products are characterized by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The diameters of ZnSe nanorods are about 200–300 nm, and the lengths are about 1–2 μm. Humidity sensors based on ZnSe nanorods are fabricated and their responsiveness to humidity on static and dynamic testing are investigated. The change of resistance is about three orders of magnitude as the relative humidity increases from 20% to 85%. The response time and recovery time is 50 s and 81 s versus the changes of relative humidity from 20% to 85% and from 85% to 20%, respectively. Our sensor offers higher sensitivity, as well as much better stability and reproducibility than the humidity sensor of ZnSe nanostructure reported before.