Narrow Results

Nanostructural zinc oxide has been successfully fabricated by heating the mixture of ZnO and graphite powders in air. The growth of these zinc oxide nanostructures with respect to the growing time and temperature has been studied. The morphologies and the crystal structures have been characterized by scanning electronic microscopy and the X-ray diffraction. The results indicated that ZnO nanostructure formed mainly along the crystal orientation [002] on silicon substrate at moderate temperatures. The crystallization was improved by prolonging growth time and the morphologies mainly depended on the distribution of the growth temperature. The growth process was attributed to vapor-liquid-solid mechanism.

ZnO nanorods and bamboo-like structures were fabricated by carbothermal evaporation in Ar gas and air atmosphere on Au-coated silicon wafers. Deposition in air atmosphere led to the fabrication of nanostructured ZnO. Investigation of substrate distance from the source material revealed that thinner nanorods are grown at shorter distances.

ZnO is known as a promising material for surface acoustic wave (SAW) sensor devices because of its piezoelectric property. Recently, quartz crystal microbalances (QCMs) have been promising as a sensor platform due to their high sensitivity and ease of measurement. In particular, the alignment of ZnO nanosheets (NSs) into ordered nanoarrays is expected to improve the device sensitivity and stability due to large specific surface area, which allows the captured significant quantities of gas molecules. In this study, we fabricated a quartz crystal microbalance sensor with ZnO NSs structures using polyvinylidene fluoride as a receptor for nerve agent detection. We synthesized two-dimensional NSs by chemical bath deposition (CBD) via the potassium hydroxide etching method. CBD is an excellent method that can easily form uniform structures at low cost. We fabricated ZnO NSs modified with polyvinylidene fluoride and used it for detection of dimethyl methylphosphonate (DMMP) gas. The NSs structure indicated that, when a similar functional group material is coated, the specific surface area increased compared to the nanorods (NRs) structure. As a result, the sensitivity of the quartz crystal microbalance sensor to DMMP gas was improved.