Synthesis of CdO nanoparticles using facile solid-state reaction and systematic study on their physical properties

Indium doped cadmium oxide nanoparticles Cd_1-xIn_xO at x = 0, 0.03, 0.05 and 0.07 were prepared using facile solid-state reaction and studied the role of indium (In) on physical properties of the Cd_1-xIn_xO nanoparticles. The synthesized nanoparticles were subjected to different characterization techniques such as XRD, FESEM, EDAX, FT-IR, UV–Vis-NIR, Raman, PL, and I–V characteristics. The XRD results confirmed that the Cd_1-xIn_xO nanoparticles were in cubic bixbyite structure with crystallite size in the range of 28 nm to 38 nm. Using the optical absorbance and reflectance spectra, the optical band gap of the Cd_1-xIn_xO nanoparticles was calculated, and it decreased from 1.81 to 1.76 eV with an increase in indium concentration. Clear peaks at 480 cm⁻¹ confirmed the metal–oxygen (Cd–O) bonding. The strong Raman modes are observed at 249.94 cm⁻¹, 261.92 cm⁻¹, 260.81 cm⁻¹, 260.53 cm⁻¹ in Raman spectra. The nanoparticle size was further confirmed by FE-SEM micrographs and histogram plots. In the PL spectra, emission peaks were observed at 423 nm, 485 nm, 532 nm, and 606 nm. The electrical properties were studied using two probe methods and the electrical resistance decreased with an increase in indium concentration.