Synthesis, field emission and humidity sensing characteristics of honeycomb-like CuO

Large-scale CuO honeycombs were synthesized via two-step electrochemical deposition. The morphology and crystal structure of the as-grown CuO honeycombs were characterized by scanning electron microscopy (SEM), x-ray diffraction and transparent electron microscopy. From the SEM images, we can find that the honeycombs were composed of well-oriented nanowires. The formation mechanism of the nanostructures was discussed. Field emission (FE) measurements demonstrated that the CuO honeycombs possessed good performance with a turn-on field of 6-7 V μm-1 and a field enhancement factor of 1361, which have promising application as a competitive cathode material in FE microelectronic devices. Due to the high surface-to-volume ratio, the humidity sensitive characteristic of the CuO honeycomb film has been investigated, which exhibits that it also has potential application in an effective and high performance humidity sensor.