Optical properties of Zinc doped tin oxide synthesized by mechanochemical processing

Abstract

Simple doping process of Zinc (Zn) with Tin oxide (SnO 2 ) was successfully prepared by the mechanochemical process, followed by a heat treatment and leaching. The raw materials are Tin Chloride (SnCl 2 ) as a base element, Sodium Carbonate (Na 2 CO 3 ) as an oxidizer and Sodium chloride (NaCl) as a diluent, while Zinc Chloride (ZnCl 2 ) as a doping element. In this paper, we with fix wavelength investigated the effect of different concentration of Zn dopant on the optical properties of SnO 2 . The chemical formula of doped SnO 2 will be Sn 1-x Zn x O 2 . The peaks of the X-ray Diffraction (XRD) prove that all Zn had been successfully doped into SnO 2 host. The average sizes of crystalline were around 25 to 44 mm and it was calculated by using Scherrer's equation. While Ultraviolet-visible spectroscopy (UV-VIS) and photoluminescence were used to analyze the energy gap differences of pure SnO 2 and doped SnO 2 with varying Zn concentration. Results show that increasing in the concentration can decrease the volume of samples. Red shift in energy gap (E g ) with an increasing Zn concentration (x ≤ 0.06) could be attributed to the Burstein-Moss effect that relates the E g with the crystallite size of SnO 2 formed before and after the doping process. The blue shift in E g at x>0.06 was possibly due to excess oxygen and may also be affected by sudden increases in crystallite size. The emission intensity was changed inversely with the E g .