ZnO nanoparticles or ZnO films: A comparison of the gas sensing capabilities

Abstract

Zinc oxide is an interesting material for bio and chemical sensors. It is a semiconducting metal oxide with potential as an integrated multisensing sensor platform, which simultaneously detects parameters like change in field effect, mass and surface resistivity. In this investigation we have used resistive sensor measurements with respect to oxygen sensitivity in order to characterize sensing layers based on electrochemically produced ZnO nanoparticles and PE-MOCVD grown ZnO films. Proper annealing procedures were developed in order to get stable sensing properties and the oxygen sensitivity towards operation temperature was investigated. The ZnO nanoparticles showed a considerably increased response to oxygen as compared to the films. Preliminary investigations were also performed regarding the response to other gases present in car exhausts or flue gases.

ZnO materials and surface tailoring for biosensing

“…The XRD diffractogram of a ZnO film presented in (Figure 9), exhibits the diffraction pattern characteristic of hexagonal ZnO with peaks corresponding to the (010), (002), (011) reflections, positioned at 2θ = 31.7°, 34.4°, and 36.2°, respectively. This is consistent with previously reported results on ZnO films and ZnO nanoparticles (29,91,95). The dominating (002) reflection peak indicates film with crystal growth with a preferred orientation along the c-axis.…”

“…The bulk ZnO sample (Figure 3a,b) was purchased from ZnOrdic (70). ZnO nanoparticles were electrochemically produced under oxidizing conditions by electrical deposition under oxidizing conditions (EDOC) (29). The as prepared particles had uniform size distribution and a high degree of crystallinity ( Figure 4).…”

“…Among the advantages of these materials is the ease of preparation while possessing high sensing performance and quantum properties. A comparison of the gas sensing capability of nanoparticles and nanostructured films has been conducted by J. Eriksson and co-authors (29). The investigation was made for oxygen detection in a carrier gas of nitrogen where it was shown that nanoparticles had higher sensitivity.…”

“…Nanoparticles and nanostructured thin films have been studied in terms of their gas sensing abilities, where it was shown that a rough surface with a larger surface area had a positive influence on the sensor response (29). As such, ZnO thin films and ZnO nanoparticles are both very interesting for electrically based biosensing (1).…”

Morphology engineering of ZnO nanostructures

“…The potential field for the porous ZnO nanostructures may be the gas storage, separation or molecular catalysis. Moreover, sensing or removing toxic, harmful or oxidizing gases (such as CO, NO x , O 2 and so on) using nanoporous materials is currently of great importance because of industrial and environmental demands [27,28]. Furthermore, if it is possible to activate a nanopore surface by external stimuli where and when desired, on-demand gas storage/trapping systems can be realized [29].…”