3.4 Sensor fabrication

The synthesized ZnO nanostructures were used for UV as well as for chemical sensing applications. ZnO nanostructures were annealed by heating it in digital


#### Table 1.

Sample details (synthesis temperature, gas flow rate, growth time).

Figure 6. Schematic illustration of chemical sensing experimental setup.

Synthesis of Metal Oxide Semiconductor Nanostructures for Gas Sensors DOI: http://dx.doi.org/10.5772/intechopen.86815

furnace at 400°C for 2 h. The annealing process was usually done for attachment of oxygen on the surface of ZnO nanostructures. The nanostructures were scratched with the help of blades, and the gaps or cuts on gold-coated quartz substrate were filled with the scratched nanostructures as shown in Figure 6. A small drop of methanol was dropped on the nanostructures with the help of 5 cc disposable syringe so that a thick paste was formed. The sensor was then placed under IR (infrared) light for 10 min for the purposes of sticking material on the quartz substrate. The experimental setup for chemical sensing is shown in Figure 6.
