Abstract
Chromium (Cr) doped CdO films are chemically sprayed and are characterized by their optical, electrical, structural, and microstructural characteristics. The thickness of the films is determined by spectroscopic ellips-ometry. The cubic crystal structure with a superior growth along (111) plane of the spray-deposited films is confirmed from the powder X-ray diffraction (XRD) analysis. XRD studies also suggested that some of the Cd2+ ions were substituted by Cr3+ ions, and the solubility of Cr in CdO is minimal, to be around similar to 0.75 wt%. The analysis by atomic force microscopy shows uniform distribution of grains throughout the surface, whose roughness is varied from 33 to 13.9 nm concerning Cr-doping concentration. The microstructures from the field emission scanning electron microscope reveal a smooth surface. The elemental composition is examined using an energy dispersive spectroscope. The micro-Raman studies carried out in room temperature endorse the presence of metal oxide (Cd-O) bond vibrations. Transmittance spectra are obtained using UV-vis-NIR spectrophotom-eter, and the band gap values are estimated from the absorption coefficient. The films show high optical transmittance (>75%) in vis-NIR region. A maximum optical band gap of 2.35 eV is obtained from 1.0 wt% Cr-doping. The electrical measurement (Hall analysis) confirmed the degeneracy nature and n-type semi -conductivity. The carrier density, carrier mobility, and dc-conductivity are increased for higher Cr-dopant per-centage. High mobility (85 cm(2)V(-1)s(-1)) is observed for 0.75 wt% Cr-doping. The 0.75 wt% Cr-doping show a remarkable response to formaldehyde gas (74.39%).