Published Paper Details:

Abstract. This research paper presents an in-depth investigation into Copper-doped Zinc oxide (Cu-ZnO) thin films, fabricated using the sol-gel dip coating method, with a focus on enhancing acetone sensing for non-invasive diabetes detection through breath analysis. The study systematically explores the structural, morphological, optical, and gas sensing characteristics of these thin films using advanced characterization techniques. The analysis of the X-ray diffraction (XRD) confirms a highly crystalline wurtzite structure in both undoped and Cu-doped ZnO thin films. The successful incorporation of copper into the ZnO lattice is evident from the shift in the XRD peaks, indicating successful doping. Scanning electron microscopy (SEM) investigations reveal changes in surface morphology with increasing copper doping concentration, including enlarged grain size and smoother film surfaces, which may impact the sensing properties. Utilising UV-visible spectrophotometry, the researchers demonstrate that Cu-doped ZnO thin films exhibit higher optical transparency compared to undoped films. Moreover, as the copper concentration increases, the optical band gap decreases, suggesting a modification in the band structure of the thin films. To evaluate gas sensing capabilities, an acetone sensing test is conducted. The results show that Cu-doped ZnO thin films outperform undoped films with an enhanced acetone sensing response. The most effective doping concentration of 3 at % of Cu results in the greatest sensitivity, with a 46% level of selectivity, a response time of 31 sec., and a recovery time of 66 sec. to acetone vapor. These results propose its potential as a non-invasive diabetes detection candidate through human breath analysis.