Detection of VOCs Using Doped ZnO Nanorods

Abstract

Metal-oxides, such as ZnO, have been popular materials of choice for the detection of VOCs because they show a relatively quick response. In this study, ZnO nanorods were prepared, first, by depositing a seed layer via atomic layer deposition (ALD) on top of a silicon substrate, and then immersing that seed layer in a chemical bath solution to facilitate growth of the rods. To enhance the gas sensing properties of the rods, some of the nanorods were doped with metals such as Au and Co. The gas sensing materials were then probed with microwaves, using Broad band dielectric Spectroscopy (BDS), to observe their changing characteristics in the presence of a VOC analyte. BDS provides and advantage in that it avoids the need for physical electrical connections which lead to errors into the measurement. Additionally, we use Raman spectroscopy to not only confirm the presence of the dopants in the nanorods, but also to help explain the behavior of the materials under microwave interrogation.