Annealing temperature effect on the structural, optical and electrical properties of ZnS thin films

• Published in: Physica. B, Condensed matter Condensed matter, 2011-04, Vol.406 (9), p.1653-1659
• Main Author: Goede, F
• Format: Article
• Language: English
• Subjects: Annealing; Barrier heights; Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Deposition; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Diffraction; Electrical properties; Electrical properties of specific thin films; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Growth from solution; II–VI semiconductors; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Permittivity (dielectric function); Physics; Surface double layers, schottky barriers, and work functions; Thin films; Zinc sulfides
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2010.12.033

Zinc sulfide thin films were prepared on glass substrates at room temperature using a chemical bath deposition method. The obtained films were annealed at temperatures ranging from 100 to 500°C in steps of 100°C for 1h. The films were characterized by X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray analysis (EDX), optical absorption spectra, and electrical measurements. X-ray diffraction analysis indicates that the deposited films have an amorphous structure, but after being annealed at 500°C, they change to slightly polycrystalline. The optical constants such as the refractive index (nr), the extinction coefficient (k), and the real (ε1) and imaginary (ε2) parts of the dielectric constant are calculated depending on the annealing temperature. Aside from the ohmic characteristics of the I–V curve, a nonlinear I–V curve owing to the Schottky contact is also found, and the barrier heights (ϕbn) for Au/n-ZnS and In/n-ZnS heterojunctions are calculated. The conductivity type was identified by the hot-probe technique. ► ZnS film was deposited on glass substrates by chemical bath deposition. ► Effect of annealing on the physical properties of the ZnS film was investigated. ► After being annealed at 500°C, amorphous film changes to slightly polycrystalline. ► Raman peaks arise due to [TOl+LA]Σ, 2TOΓ, 2LO, 3LO phonon modes of ZnS. ► A nonlinear I–V curve owing to the Schottky contact is also found.