Optical and Structural Characterization of CdTe Nanoparticles Synthesized Using Chemical Bath Deposition Technique

The purpose of this research is the elaboration of cadmium telluride nanoparticles by using the chemical bath deposition technique. The formulation procedure consists of preparing tellurium ions (Te-2) and combination of tellurium ion solution with deionized water, cadmium chloride, and polyethyleneimine (PEI). The nanoparticles were synthesized at three different concentrations denoted C1, C2, and C3. Furthermore, for each CdTe, nanoparticles were obtained with absorption edges at 404.02 nm, 428 nm and 452.66 nm related to C1, C2, and C3, respectively. Also, the direct energy gaps of CdTe nanoparticle semiconductors were: Eg(C1) = 3.07 eV, Eg(C2) = 2.9 eV, and Eg(C3) = 2.74 eV. Transmission electron microscopy (TEM) indicated three different average diameter sizes of a single nanoparticle: D(C1) = 3.23 nm, D(C2) = 6.46 nm, and D(C3) = 7.73 nm with average sizes of 6.11 nm, 5.29 nm, and 9.76 nm, respectively. The fast Fourier transform of TEM contrast micrographs corresponded with a hexagonal structure. The presence of Cd, Te, and TeO2 was identified by x-ray photoelectron spectroscopy. Raman spectroscopy was used to identify three peaks at 122 cm(-1), 140 cm(-1) and 165 cm(-1) that proved the formation of CdTe nanoparticles.