An Investigation of Pb-Contribution Effect on the Characteristic Features of CdO Films Coated with a Sol-Gel Spin Coating Technique

Abstract

Lead (Pb)-loaded CdO films have been firstly fabricated with a sol-gel spin coating apparatus. Pb-contribution ratio was changed from 0 to 5 at.% in the step of 1 at.%. The impact of Pb-contribution ratio on the crystalline, surface, and optical characters of CdO was examined with XRD, XPS, SEM, AFM, and UV/VIS spectrophotometer measurements. The polycrystalline cubic CdO nano-particles with (111) preferential direction were observed for the whole samples. Although the value of average crystallite size of pure CdO continuously increased with Pb-loading, the dislocation density value decreased with Pb-contribution content. The nano-sized spherical granules with a c-axis columnar structure were also seen from SEM and AFM images. The RMS roughness values were found to be an increasing tendency from 5.97 to the values of 8.28 nm, 8.89, 17.9, 22.7, and 39.3 nm with Pb-loading content. The optical studies showed that the band gap and Urbach energy values of pure CdO initially increased from 2.61 eV and 371 meV to 2.76 eV and 390 meV with 3 at.% Pb-content, then they went down with more Pb-contents. As a result of this investigation, it can be concluded that Pb-contribution level has a significant influence on the properties of CdO.