Influence of Sn doping on structural, optical and electrical properties of ZnO thin films prepared by cost effective sol–gel process

Abstract

Tin (Sn) doped zinc oxide (ZnO) thin films were synthesized by sol–gel spin coating method using zinc acetate di-hydrate and tin chloride di-hydrate as the precursor materials. The films were deposited on glass and silicon substrates and annealed at different temperatures in air ambient. The agglomeration of grains was observed by the addition of Sn in ZnO film with an average grain size of 60nm. The optical properties of the films were studied using UV–VIS–NIR spectrophotometer. The optical band gap energies were estimated at different concentrations of Sn. The MOS capacitors were fabricated using Sn doped ZnO films. The capacitance–voltage (C–V), dissipation vs. voltage (D–V) and current–voltage (I–V) characteristics were studied and the electrical resistivity and dielectric constant were estimated. The porosity and surface area of the films were increased with the doping of Sn which makes these films suitable for opto-electronic applications.