Structural, Optical and Electrical Properties of Spray Pyrolysis Deposited CdS:Fe Thin Films

Abstract

Thin films of undoped and Fe-doped cadmium sulphide were deposited by spray pyrolysis technique using a perfume atomizer on glass substrate kept at 400°C. The films were prepared with a [Fe]/[Cd] ratio equal to (0at%, 1at%, 3at%, 5at% and 7at%) and their structural morphological optical and electrical properties were investigated through XRD, SEM, UV-Vis spectrometry and four probe point measurement respectively. XRD diffraction spectra revealed the polycrystalline nature of the films, with hexagonal structure and (101) as a preferential direction. The SEM images showed a surface structure dense composed of crystallites whose average size increase with the increasing of [Fe]/[Cd] ratio. According to UVVis spectrometry all films were transparent and their transmittance in the visible region varies between 70% and 90% depending on the [Fe]/[Cd] ratio, the calculated band gap decrease when the [Fe]/[Cd] ratio increases. The measured electrical resistivity of the films decrease to a minimum value equal to 5,6.104 Ω.cm found for film obtained with [Fe]/[Cd] ratio equal to 3at%.