Date of Graduation

2014

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Konstantinos Sierros

Committee Co-Chair

Darran Cairns

Committee Member

Stephen Kukureka

Abstract

Transparent conducting oxides (TCO's) are widely adopted coatings applied to a wide range of applications including; optoelectronics, touch-screens, smart systems, organic light emitting diodes (OLED's), and solar panel technologies. During both fabrication and service, the mechanical reliability of these coatings, such as wear and scratch resistance, is of great importance. Zinc Oxide (ZnO) coatings have emerged as a highly desirable, and low cost alternative to the commonly adopted Indium Tin Oxide (ITO) since they offer; wide band gap energy (3.34eV), high optical transmission, and are both chemically and thermally stable.;In this work, the mechanical properties of sol-gel ZnO films deposited on soda lime glass substrates via the dip coating method was investigated. The objective of this work is to study the influence of differing annealing temperatures may have on the structural, optical, and mechanical properties of sol-gel ZnO films. For this purpose; x-ray diffraction, nanoindentation, scratch testing, and tribological techniques were utilized in order to gain an understanding of how the sol-gel ZnO films properties are affected as annealing temperature is increased. Structural analysis indicated that all films were polycrystalline with a wurtzite structure and displayed an increase in crystallinity as the annealing temperature was increased. Using nanoindentation it was observed that the Hardness and Young's Modulus increased from 1.79+/-0.57 to 2.68+/-0.87 GPa and 70.19+/-17.89 to 73.72+/-11.84 GPa respectively as a result of increasing annealing temperature. Tribological and scratch testing techniques indicated that the adhesion properties of ZnO films were also improved as a result of increased annealing temperature. On the other hand, optical transmission had been significantly reduced as a result of increasing grain size and coating thickness at higher annealing temperatures.

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