H. Metin

Annealing effects on optical and crystallographic properties of CBD grown CdS films

CdS films were prepared by chemical bath deposition (CBD) at 60 °C without stirring. The crystallographic structure of the films and the size of the crystallites in the films were studied by x-ray diffraction. The energy gap of the films was found to decrease by annealing. The best annealing temperature for CBD grown CdS films was found to be 350 °C from optical properties. The crystallite sizes were found to increase and the x-ray diffraction patterns were seen to sharpen by annealing. The optical properties of the films were seen to be dependent on the film thicknesses. The band edge sharpness of optical absorption was seen to oscillate by thermal annealing. Self-oxidation and sulfur evaporation were found to be responsible for this oscillating behaviour. Annealing over 400 °C was seen to degrade the optical properties of the film.

The effect of annealing temperature on the structural, optical, and electrical properties of CdS films

Cadmium sulfide (CdS) photocatalyst films were grown on glass by chemical bath deposition (pH 9.4, 70 °C) and then annealed in nitrogen from 423 K to 823 K in steps of 100 K. The XRD crystallite size increases in a sigmoidal manner from 60 nm to 100 nm while the optical band gap energy decreases from 2.42 eV to 2.28 eV. This trend is paralleled by the decreasing Urbach energy, but only up to 623 K, where it increases again. This is the temperature where the Cd effectively surpasses the phase transformation from cubic to hexagonal, and the activation energy for electronic transport drops by a factor of nearly two.

Cadmium Sulfide Thin Films Grown By Chemical Bath Deposition Method

CdS thin films were deposited by the chemical bath deposition (CBD) from a bath containing CdSO4, thiourea and ammonia. The effect of annealing in air on the optical properties of CdS thin films was investigated. The quality of CBD CdS thin films was analyzed at different condition of temperature, concentration of reactants and deposition time. The optical band gap of the films was estimated using the optical transmittance measurements. A decrease in the band gap was observed for the annealed films. The room temperature resistivity was found to be 1.67×109Ω‐cm. The activation energy was found to be 0.45 eV.

Structural and Optical Properties of Cadmium Selenide Films Prepared by Chemical Bath Deposition

Cadmium selenide (CdSe) thin films were deposited by a simple and inexpensive chemical bath deposition (CBD). The films were deposited using cadmium nitrate as a Cd2+ ion source and sodium selenosulfate as a Se2− ion source. The films were characterized by using X‐ray diffraction, optical absorption and electrical measurements. The values of the optical band gap energy. Eg, calculated from the absorption spectra, ranged between 1.70 and 1.83 eV. The room temperature resistivity was found to be 12×107Ω‐cm. The activation energy is found to be 0.34 eV.