An Effect of Precursor Concentration on ZnO Thin Films Prepared by Dip Coating Method

K. Radhi Devi; G. Selvan; M. Karunakaran; K. Kasirajan; G. Rajesh Kanna; S. Maheswari

K. Radhi Devi Department of Physics, Sethupathy Govt. Arts College, Ramanathapuram- 623 502, India.
G. Selvan Department of Physics, Thanthai Hans Roever College, Perambalur - 621 220, India.
M. Karunakaran Department of Physics, Alagappa Government Arts College, Karaikudi � 630 003, India.
K. Kasirajan Department of Physics, Alagappa Government Arts College, Karaikudi � 630 003, India.
G. Rajesh Kanna Department of Electronics, Government Arts College for Women, Ramanathapuram- 623 502, India.
S. Maheswari Department of Physics, Alagappa Government Arts College, Karaikudi � 630 003, India and Department of Physics, Caussanel College of Arts and Science, Ramanathapuram - 623 523, India.

Keywords: Zinc oxide, thin films, structural studies, morphological studies, optical properties, band gap

Abstract

Zinc Oxide (ZnO) thin films have been successfully coated onto glass substrates at various solutions concentration (0.1 M, 0.2 M and 0.3 M) by Low cost SILAR coating technique. The film thickness was estimated using weight gain method and it revealed that the film thickness increased with solution concentration values. The prepared film structural, morphological and optical properties were studied using X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-Vis-NIR spectrophotometer respectively. The structure of the films were found to be hexagonal structure with polycrystalline in nature with preferential orientation along (002) plane. X-ray line profile analysis was used to evaluate the micro structural parameters such as crystallite size, micro strain, dislocation density and stacking fault probability. The value of the crystalline size is increased by increasing the concentration of the solution. The average crystalline size was estimated at in the range of 26 nm to 29 nm. The morphological results showed that the concentration of a solution had a significant effect on the morphology of the ZnO thin films. The optical studies revealed that the band gap can be tailored between 3.65 eV to 3.85 eV by altering solution concentration. EDAX studies have shown the presence of zinc and oxygen content. Photoluminescence intensity varies with molar concentration due to the increase of oxygen vacancies. FTIR results conforms the presence of functional group present in the samples.