Fabrication and improved response of ZnO-CdO composite films under different laser irradiation dose

Abstract

Promising Zinc Oxide (ZnO) and Cadmium Oxide (CdO) alloy (ZnO-CdO) films were fabricated on glass substrates by screen printing route for optoelectronic applications. The Nd:YAG green diode laser of wavelength 532 nm and laser fluence of 1.8 J/cm2 was used to irradiate the fabricated films at room temperature. The characterization of these films were systematically studied by means of X-ray diffraction (XRD), UV–vis, photoluminescence (PL), Raman spectroscopy and two probe method for conductivity measurement. The XRD pattern shows that all the films were well crystallized with maximum diffraction of (101) plane and mixed phases of ZnO and CdO were detected. The structure, space group and other crystal related parameters were confirmed from Rietveld refinement of XRD data. The basic optical parameters (band gap, refractive index and extinction coefficient) have been estimated using absorbance spectra. The PL spectrum of ZnO-CdO composite films exhibits red shift and blue- green emissions shift upon laser irradiation were confirmed from CIE 1931 diagram. The Raman spectroscopy indicates that the quality of the ZnO-CdO films was increased while their structure defects were increased. DC conductivity measurement confirms semiconductor behaviour. All the parameters such as particle size, optical constants, colour emission and activation energy have been significantly improved upon laser irradiations dose of 1.8 J/cm2 for different durations of time. This study could be appropriate for optoelectronic applications.