Improvement in micro-structural and mechanical properties of zinc film by surface treatment with low temperature argon plasma

Abstract

Nanocrystalline zinc films were deposited on gold coated borosilicate glass substrates by thermal evaporation method using zinc powders as the source material and then treated with argon plasma at various temperatures. From X-ray diffraction study, the as-deposited films are found to be metallic Zn and polycrystalline in nature. The crystalline nature improves with the increase of temperature up to 200 degrees C and decreases with the further increase of temperature to 300 degrees C. The binding energy observed for Zn 2p(3/2), and the binding energy separation between Zn 2p(3/2) and Zn 2p(1/2) in the X-ray photoelectron spectrum indicate that the films are metallic zinc films. Transmission electron microscopic study shows hexagonal shaped grains having size similar to 58 nm upon treatment with Ar plasma. It is clearly shown the grain growth and distinct grain boundary with the increase in temperature. The average Young's modulus (E) and hardness (H) are measured to be 84 GPa and 4.0 GPa for as-deposited film, whereas 98 GPa and 5.8 GPa for plasma treated film at 200 degrees C. The enhancement in mechanical properties is attributed to improvement in crystalline nature of the film and better interlinking between grains and boundaries. (C) 2011 Elsevier B.V. All rights reserved.