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Comparitive study of solution grown Strontium fluoride (SrF<sub>2</sub>) and Berillium iodide (BeI<sub>2</sub>) thin films and their possible applications


P A Ilenikhena

Abstract



Semi conducting halide thin films of strontium fluoride (SrF2) and berylium iodide (BeI2) were successfully deposited on glass slides at 320K and pH of 8, 9, 10 and 12 using solution growth technique. A complexing agent, ethylenediamine-tetra acetate (EDTA), with pH oppose that of bath constitutions, was used to bath reagents to enhance control and stabilize the deposition pH at different values suitable for film growth. X-ray diffraction method was used to confirm the depositions. Electron micrographs of the films reveal uniform surface depositions. Absorbance (A) spectra data were measured by a single beam spectrophotometer (Pharmacia LKB Biochrom 4060) at wavelength range 200nm to 900nm. Other optical and solid state properties were calculated from the data and compared with other deposited thin films. The average optical and solid state properties of strontium fluoride thin films include absorbance ranging from 0.034 to 0.086, transmittance 0.820 to 0.925, refractive index 1.51 to 1.88, electrical conductivity 0.40 to 0.49(ohm-cm)–1, film thickness 0.013 to 0.074μm and band gap 2.65 to 2.75 + 0.05eV. For berylium iodide films the absorbance ranges from 0.204 to 0.302, transmittance 0.499 to 0.625, refractive index 2.41 to 2.61, electrical conductivity 0.62 to 0.68(ohm-cm) –1, film thickness 0.202 to 0.362μm and band gap 2.20 to 2.75 + 0.05eV. Films with refractive index lower than 1.9 could be employed in antireflection coatings, eyeglass coating and solar thermal control coatings. Those with refractive index greater than 1.9, could be useful in construction of poultry houses, solar cells and anti dazzling coatings.

Journal of Science and Technology Vol. 26 (3) 2003: pp. 11-11

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eISSN: 0855-0395