Morphological, optical and structural analysis in CdS, CdS-CdCO3 and CdCO3 thin solid films grown by chemical bath

CdS, CdS-CdCO3 and CdCO3 thin films grown by chemical bath at ∼80, ∼60 and ∼40 °C temperature range were prepared. Morphology and size showed changes as a variety of truncated cube-shaped structures, wires and circles. Energy band gap was ∼2.4 eV (CdS) and ∼4.0 eV (CdCO3), respectively. XRD showed wurtzite crystalline phase for CdS films and a rhombohedral phase for CdCO3. Raman spectra in CdS exhibited a peak for A1(TO) phonon corresponding to wurzite and CdCO3 film showed internal vibrations of CO32− group: v1-symmetric stretching (∼1090 cm−1) v3-asymmetric CO stretching (∼1401 cm−1); v4-in-plane band of the CO32− ions and two bands assigned to translations and release of the CO32− group relative to the Cd atoms: v13 (∼274 cm−1), v14 (∼169 cm−1). Lattice modes v13 (∼274 cm−1), v3- asymmetric CO stretching (∼1401 cm−1), v1-symmetric CO stretching ∼1090 cm−1 were also noted. Finally, a simple thermodynamic analysis is presented to understand the formation of the compounds by calculations of Gibbs free energy and data associated with the corresponding ions of the CdS and CdCO3 materials in our working conditions.