Growth and Characterization of CdSe_{1 − y}S _y Nanofilms Obtained by Chemical Bath Deposition

In this work, the growth and characterization of cadmium selenide sulphur (CdSe_{1 − y}S_y) deposited by chemical bath deposition (CBD) technique at the reservoir temperature of 20 ± 2 °C are presented, varying the thiourea volume added to the growth solution in the range of 0–30 ml. The films chemical stoichiometry was determined by energy-dispersive X-ray spectroscopy (EDS). The X-ray diffraction (XRD) analysis and Raman scattering reveal that CdSe_{1 − y}S_y-deposited films showed hexagonal wurtzite crystalline phase. The average size of the crystalline grain in relation to the sulphur volume varies in the range of 1.48–9.2 nm that was determined by using the Debye-Scherrer equation for the direction (100), which is confirmed by analyzing the grain average diameter by high-resolution transmission electron microscopy (HRTEM). Raman scattering shows that the lattice dynamics is characteristic of bimodal behaviour and the multipeak adjust of the first optical longitudinal mode for the CdSeS denotes, in all cases, the Raman shift of the characteristic peak in the range of 177–181 cm⁻¹ of the CdSe crystals associated with the sulphur incorporation. CdSe_{1 − y}S_y band gap energy can be varied from 1.86 to 2.11 eV by varying the thiourea volume added in the growth solution measured by transmittance at room temperature.