ZnO nanowires grown on bulk ZnO coatings: Mechanical response to deep cryogenic treatment

ZnO nanowires are currently used in many application fields, such emission displays, dye-sensitized solar cells, gas sensors, nanomachines, to cite but few. Thermal stability is often a concern in terms of the mechanical response and, in particular, for the elasticity of the nanowires. Literature works focused to a certain degree, on the heating response of nanowires. Anyhow, no experimental data are nowadays available in literature on the low- And very low-temperature exposures. In the present study, deep-cryogenic treatment was performed on vertically aligned ZnO nanowires produced by metal organic chemical vapor deposition. The mechanical response of the nanowires was detected by nanoindentation tests. It was found that the Young's modulus, the critical buckling stress and strain of individual nanowires is not significantly influenced by the cryogenic exposure. Yet, the bulk base ZnO from which the nanowires are grown halved after the deep-cryogenic treatment.