title: Effect of complexing agent and annealing atmosphere on properties of nanocrystalline ZnS thin films.
abstract: The nanocrystalline Zinc Sulfide (ZnS) thin films were prepared on glass substrates by chemical bath deposition (CBD) method using aqueous solutions of zinc acetate, thiourea and tri-sodium citrate in alkaline medium at 80 degrees C. The tri-sodium citrate acts as a complexing agent. The effects of complexing agent and annealing atmosphere (95%N2 + 5%H2S) on structural, morphological and optical properties of ZnS thin films were studied using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and optical absorption. XRD study revealed that single phase ZnS powder was formed in the solution with tri-sodium citrate, however, ZnS and ZnO mixed phase powder was formed in the solution without tri-sodium citrate. The films deposited with trisodium citrate showed ZnS with hexagonal wurtzite phase. However, annealed film in (N2 + H2S) atmosphere showed cubic (zincblende) phase. FE-SEM images show that grain size of as-deposited and annealed ZnS films are about 20 nm and 50 nm, respectively. Optical absorption study showed that the films have moderate optical transmission from 65% to 75% in the visible region and the optical band gap energy of as-deposited ZnS film is 3.91 eV and it decreases to 3.73 eV after annealing.
authors.affiliation: Department of Materials Science and Engineering, Chonnam National University, Gwangju 500-757, Korea.
authors.forename: Seung Wook
authors.initials: SW
authors.lastname: Shin
authors.forename: Hyun Pil
authors.initials: HP
authors.lastname: Oh
authors.forename: S M
authors.initials: SM
authors.lastname: Pawar
authors.forename: Jong-Ha
authors.initials: JH
authors.lastname: Moon
authors.forename: Jin Hyeok
authors.initials: JH
authors.lastname: Kim