Room temperature chemo-resistive sensor based on two dimensional ZnO nanoflakes for ammonia detection
- Country : India
- Subject : Chemistry
Ammonia detection in the atmosphere is an extremely significant requirement with implications to the environment and living beings. In this current era of technology, there is a great demand for highly sensitive, compatible, low-cost portable sensors for the fabrication and improvement of sensing device performance. In this work, the ZnO nanoflakes were grown by a modified aqueous method on n-type silicon substrate, where zinc nitrate, hexamethylenetetramine (HMTA) and aluminum nitrate nonahydrate were taken as precursors. The structural and morphological properties with various concentration of aluminum were investigated using scanning electron microscopy (SEM) and X-Ray diffraction (XRD) techniques. Flakes-like nanostructures were observed by the SEM studies. The X-ray diffraction pattern has shown the evolution of (002) and (103) peaks for ZnO nanostructures. On the other hand, ZnO nanorods were grown on silicon substrates using Zinc nitrate and HMTA. The average length and width of the ZnO nanorods was found to be around 2-3 µm and 350-410 nm, respectively. A comparative study on the ammonia sensing behaviour of hydrothermally grown ZnO nanoflakes and nanorods were carried out by current-voltage measurement technique at room temperature. ZnO nanoflakes showed higher response rate for ammonia detection than as-grown ZnO nanorods.