An Effect of Precursor Concentration on ZnO Thin Films Prepared by Dip Coating Method | Chapter 08 | New Insights on Chemical Research Vol. 1

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.

Author(s) Details

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.

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Reflections on the Use of Density Functional Theory in the Understanding of the Effects of Moderate Amounts of Sulfur Substitutional Impurities on ZnO | Chapter 06 | New Advances in Materials Science and Engineering Vol. 1

A theoretical study on the effects of a moderate amount of sulfur when used as substituent impurity in place of oxygen in zinc oxide at its crystal form using Density Functional Theory (DFT). S-substituent amounts in percent go from 0.1% up to 1.0% and we analyze modifications in the crystal properties such as lattice characteristics, total energy, and gap energy. Lattice parameter c increased slightly as S-substituent percent increased, lattice parameter a had an opposite behavior because it decreased as the S-substituent increased and c/a rate had ups and downs but with very slight variation between consecutive values. Total energy calculations showed an increasing trend at all times and binding energy showed a decreasing trend at all times as the substituent percent increase but the variation between consecutive points was small. Gap energy had a decreasing trend with a maximum variation of 6.57% at 1.0% S substituent from pristine ZnO. In order to correct the DFT underestimation of gap energy we applied a correction factor and found a decreasing trend as the substituent percent increase and observed the highest difference from undoped ZnO was 1.42% at 1.0% S-substituent. We study the effects on the ZnO structure occurring when moderate S-substituent amounts from 0.1% to 1.0% are used and provide new knowledge to predict if the geometric and electronic structure changes may be suitable for new applications of ZnO in optoelectronics.

Author(s) Details

Manuel Alberto Flores-Hidalgo
Facultad de Ciencias Qu´ımicas, Universidad Ju´arez del Estado de Durango, Durango, Durango 34120, Mexico.

Diana Barraza-Jim´enez
Facultad de Ciencias Qu´ımicas, Universidad Ju´arez del Estado de Durango, Durango, Durango 34120, Mexico.

Daniel Glossman-Mitnik
Laboratorio Virtual NANOCOSMOS, Departamento de Medio Ambiente y Energ´ıa, Centro de Investi- gaci´on en Materiales Avanzados, Chihuahua, Chih 31136, Mexico.

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