The effect of Fe-dopant concentration on ethanol gas sensing properties of Fe doped ZnO/ZnO shell/core nanorods

Abstract

In this paper, Fe doped-ZnO/ZnO shell/core nanostructures were synthesized through a simple two-step method and the effects of Fe dopant concentrations (between 0-9 at.%) on the structural, electrical and gas sensing properties were investigated. The X-ray diffraction analysis revealed that all of the samples are crystallized in the same wurtzite hexagonal crystal structure with (002) peak as the main orientation. Nevertheless, the morphology of shell/core nanorods remained stable with increasing of Fe dopant, but the crystallinity improved. The Ultraviolet -Visible spectroscopy analysis showed that the Fe ions have coordination number of 3+ in the ZnO shell layer. The participation of Fe3+ ions into ZnO layer was also confirmed by Current-Voltage (I-V) curves where the resistance of nanorods was reduced with Fe concentration. Moreover, the ethanol-sensing properties of the Fe-doped ZnO/ZnO shell/core nanorod sensors were systematically investigated. According to the results, optimum gas sensing was obtained by the addition of 0.5 at.% Fe to ZnO shell layer which lead to significant enhancement in ethanol gas response.