Mn-doped ZnO nanorod gas sensor for oxygen detection

In this work, we have used resistive sensor measurements regarding the oxygen gas sensitivity of un-doped and Mn-doped ZnO nanorods prepared by microwave-hydrothermal method. X-ray diffraction (XRD) results indicated that the Mn-doped ZnO nanorods have single phase nature with the wurtzite structure. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) results suggested that Mn-doped ZnO nanorods possessed higher aspect ratio (27) than un-doped ZnO (24). The selected area electron diffraction (SAED) pattern inferred that the ZnO nanorods have single crystalline nature with preferentially growth along [001] direction. Raman scattering spectra of Mn-doped ZnO nanorods revealed the modification in E2 (high) mode that is related to the vibration of oxygen atoms in wurtzite ZnO, suggested the successful doping of Mn into Zn site in ZnO. The gas sensing properties measured at room temperature revealed that the Mn-doped ZnO nanorods exhibited high sensitivity as compared to un-doped ZnO.

► Mn-doped ZnO nanorods using microwave-hydrothermal have been prepared. ► XRD and TEM results revealed the single phase nature of Zn1−xMnxO nanorods. ► Modification in the intensity of E2 (high) mode and sub-band edge emissions by doping of Mn into ZnO. ► The value of resistance increased with the increase of oxygen gas concentration in the chamber. ► Mn-doped ZnO nanorod sensor has significantly better sensing performance than un-doped ZnO nanorod.