Synthesis and Characterization of Pure and Cu-doped NiO Thin Films for Detection of Ethanol

Abstract

Herein, a highly sensitive, selective and stable ethanol sensor based on nanostructured Cu doped NiO thin films is reported. Pure and Cu doped NiO thin films were prepared using spray pyrolysis technique with different copper concentrations. The XRD, Raman, SEM, XPS and TEM were used to investigate the structural, morphological and compositional properties of deposited films. The XRD studies confirmed that deposited films exhibit cubic structure with polycrystalline nature. Raman spectroscopy of the deposited NiO based thin film reveals as single-phonon first-order longitudinal-optical LO mode and double-phonon second-order longitudinal-optical mode 2LO. Scanning electron microscopy (SEM) has demonstrated a significant variation in the morphology of the coated films. X-ray photoelectron spectroscopy (XPS) results revealed that successful doping of copper in NiO matrix, whereas TEM investigations revealed a nanometric crystal size in Cu doped NiO. Gas sensing performance of the deposited thin films was measured using static distribution technique towards 50 ppm ethanol gas at room temperature. Cu doped NiO thin film (4 wt.% ) has shown improved sensing features towards 50 ppm of ethanol with good selective, sensitive and stable features with quick response and recovery characteristics.