Effect of doping concentration on the structural and optical properties of pure and tin doped zinc oxide thin films by nebulizer spray pyrolysis (NSP) technique

Pure and tin doped zinc oxide (Sn:ZnO) thin films were prepared for the first time by NSP technique using aqueous solutions of zinc acetate dehydrate, tin (IV) chloride fendahydrate and methanol. X-ray diffraction patterns confirm that the films are polycrystalline in nature exhibiting hexagonal wurtzite type, with (0 0 2) as preferred orientation. The structural parameters such as lattice constant (‘a’ and ‘c’), crystallite size, dislocation density, micro strain, stress and texture coefficient were calculated from X-ray diffraction studies. Surface morphology was found to be modified with increasing Sn doping concentration. The ZnO films have high transmittance 85% in the visible region, and the transmittance is found to be decreased with the increase of Sn doping concentration. The corresponding optical band gap decreases from 3.25 to 3.08 eV. Room temperature photoluminescence reveals the sharp emission of strong UV peak at 400 nm (3.10 eV) and a strong sharp green luminescence at 528 nm (2.34 eV) in the Sn doped ZnO films. The electrical resistivity is found to be 106 Ω-cm at higher temperature and 105 Ω-cm at lower temperature.

– Flower shape and vertical hexagonal nano-rods constructed by Sn doped ZnO film successfully prepared by NSP technique. – For Sn dopants (upto 1%), an apparent vertical hexagonal nano-rods structure with average diameter ∼68 nm. – The grain size slightly increases with increasing Sn dopants upto 15%, and the average diameter of Sn:ZnO film is ∼78 nm.Figure optionsDownload as PowerPoint slideHighlights
► NSP technique is very easy, safely, cheap non-vacuum system of deposition.
► NSP method for large area coatings and good results as compared with other methods.
► NSP technique is suitable for the preparation of smooth and uniform films.
► Sn doped ZnO films are suitable for sensors and solar cells.