Effect of deposition temperature on the structural and optical properties of CdSe QDs thin films deposited by CBD method

• Synthesis of CdSe QDs with l-Cysteine capping agent for applications in nanodevices.
• The films of CdSe QDs present uniform and good dispersive particles at the surface.
• Effect of bath temperature on the structural and optical properties of CdSe QDs thin films.
• Investigation of the optical constants and dispersion parameters of CdSe QDs thin films.

Cadmium selenide quantum dots (CdSe QDs) thin films were deposited onto glass substrates by a chemical bath deposition (CBD) method at different temperatures from an aqueous solution containing l-Cysteine (l-Cys) as capping agent. The evolution of the surface morphology and elemental composition of the CdSe films were studied by AFM, SEM, and EDX analyses. Structural and optical properties of CdSe thin films were investigated by XRD, UV–vis and PL spectroscopy. The dispersion behavior of the refractive index is described using the single oscillator Wemple-DiDomenico (W-D) model, and the physical dispersion parameters are calculated as a function of deposition temperature. The dispersive optical parameters such as average oscillator energy (Eo), dispersion energy (Ed), and static refractive index (no) were found to vary with the deposition temperature. Besides, the electrical free carrier susceptibility (χe) and the carrier concentration of the effective mass ratio (N/m*) were evaluated according to the Spitzer-Fan model.

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