Effect of doping concentration on the structural, morphological, optical and electrical properties of Mn-doped CdO thin films

Thin films of manganese-doped cadmium oxide (CdO:Mn) with different Mn-doping levels (0, 1, 2, 3 and 4 at.%) were deposited on glass substrates by employing an inexpensive, simplified spray technique using a perfume atomizer at 375 °C. The influence of Mn incorporation on the structural, morphological, optical and electrical properties of CdO films has been studied. All the films exhibit cubic crystal structure with a (1 1 1) preferential orientation. Mn-doping causes a slight shift of the (1 1 1) diffraction peak towards higher angle. The crystallite size of the films is found to decrease from 34.63 nm to 17.68 nm with an increase in Mn doping concentration. The CdO:Mn film coated with 1 at.% Mn exhibit a high transparency of nearly 90 % which decreases for higher doping concentration. The optical band gap decreases with an increase in Mn doping concentration. All the films have electrical resistivity of the order of 10⁻⁴ Ω·cm.