Construction of Cu doped ZnO nanorods by chemical method for Low temperature detection of NO2 gas

• Published in: Sensors and actuators. A. Physical. Vol. 299; p. 111611
• Main Authors: Patil, V.L., Vanalakar, S.A., Tarwal, N.L., Patil, A.P., Dongale, T.D., Kim, J.H., Patil, P.S.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.11.2019; Elsevier BV
• Subjects: Annealing; Coordination compounds; Copper; Cu-doped ZnO nanostructures; Electrical equipment; Electrical properties; Electrical resistivity; Field emission microscopy; Gas sensor; Gas sensors; Low temperature; Morphology; Nanorods; Nitrogen dioxide; NO2; Operating temperature; Optical properties; Organic chemistry; Photoluminescence; Scanning electron microscopy; Thin films; Zinc oxide; Zinc oxides; Thin films; NO2; Gas sensor; Cu-doped ZnO nanostructures; Nanorods
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2019.111611

[Display omitted] •Synthesis of Cu-doped rod-like ZnO nanostructured thin films by a simple wet chemical method.•The Cu doping modifies the surface morphology and conductivity of ZnO thin films.•As per the author’s knowledge, this is the first report on NO2 gas sensing with Cu doped ZnO Nanorods.•The Cu doped ZnO exhibited the gas response of ˜ 71 for 1 ppm NO2 gas at low operating Temperatures. In this report, we have prepared Cu-doped ZnO nanorods by a simplistic wet chemical method with subsequent annealing. The phase formation, optical, surface morphological studies along with the electrical properties of the Cu doped ZnO thin films were characterized by X-ray diffraction (XRD), photoluminescence (PL), field emission scanning electron microscopy (FESEM) and Hall measurements, respectively. The addition of copper (Cu) in to the matrix of ZnO influenced the surface morphology of the product dramatically. The regular hexagonal nanorods-like surface morphology of ZnO becomes a broken rod-like morphology, after addition of copper. Owing to the complexes surface morphology of Cu doped ZnO, the system was used to detect the toxic gases like NO2. The effect of doping on the gas-sensing properties of ZnO was slightly counterintuitive in that they initially increased up to Cu concentrations of 1% before beginning to decline. Meanwhile, the Cu doped ZnO exhibited the gas response of ˜ 71 for 1 ppm of NO2 gas at low operating temperatures. This higher gas sensing response is due to the defect states observed in Cu doped ZnO films. In addition to above mentioned findings, the transformation of n-type ZnO to p-type Cu doped ZnO was also observed. The p-type conductivity is attributed to the holes created in the merging of Cu on Zn sites.