Obtaining and characterization of p type Si and conductive substrated CdS heterojunctions by chemical bath deposition method

In this thesis study, 3 groups of CdS semiconductor thin films were obtained by using the chemical bath deposition (CBD) method with solutions of different molarity. The 1st group CdS films were deposited on glass, glass/ITO, glass/FTO, and p-type Si substrates using the CBD method at 85 °C for 25 minutes, while the 2nd group CdS films were deposited on the same substrates as the 1st group at 85 °C for 40 minutes On the other hand, the 3rd group films were obtained using the 2nd group film solution on the glass substrate in 35 minutes. One of the films was annealed at 623 K in a nitrogen environment. The films were characterized by UV-Visible Spectrophotometer, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), Raman spectroscopy, Hall effect measurement system and Fourier Transform Infrared (FT-IR) spectroscopy, Linear Scanning Voltammetry (LSV) and amperometry measurement. It was observed that the surface morphology of the 1st group CdS films was in the nanoparticle structure like a sphere, while the 2nd and 3rd group films were in the nanowall structure. All of the films are polycrystalline and n-type. The rank of the resistivities of the 1st group films are 104 on glass/CdS,10-4 on glass/ITO/CdS, 10-4 on glass/FTO/CdS10-4 and 10-6 onp-Si/CdS. The 2nd group films of the resistivities are in the order of glass/CdS 105, glass/ITO/CdS 103, glass/FTO/CdS 104 and p-Si/CdS 105-cm. The rank of the resistivity of 3rd group films increased from 104 to 105 by annealing. The optical band gaps (Eg) of 1st group films are 2.33 eV on glass/CdS,2.36 eV onglass/ITO/CdS and 2.39 eV on glass/FTO/CdS eV. The optical band gaps of 2nd group films are 2.21eV on glass/CdS, 2.12 eVon glass/ITO/CdS and 2.29 eV on glass/FTO/CdS. The optical band gap of the 3rd group films decreased from 2.31 eV to 2.19 eV by annealing. According to the LSV analysis results of the 1st and 2nd group films, the highest current value was found in the ITO substrate in the 1st group and in the FTO in the 2nd group. These results are consistent with the amperometry measurement ones. The 1st group films are good candidates for solar cells and optoelectronic devices with their high conductivity, while 2nd and 3rd group films show promise with their nanowall properties.