Date of Graduation

Spring 2017

Degree

Master of Science in Materials Science

Department

Physics, Astronomy, and Materials Science

Committee Chair

Robert Mayanovic

Keywords

femtosecond PLD, tungsten bronzes, tungsten oxide thin films, nanosecond PLD, thin film morphology

Subject Categories

Materials Science and Engineering

Abstract

Pulsed laser deposition (PLD) is a promising technique for creating inexpensive,nanostructured thin films which may lead to structures suitable for photocatalysis. During this study, multiple tungsten oxide thin films were prepared using two types of PLD techniques. The first method was conducted at US Photonics, Springfield, MO, using a femtosecond laser while the second method relied on use of an excimer (nanosecond) laser located at Missouri State University. Films were first deposited on glass using both methods at room temperature. Further study was conducted on thin films deposited on sapphire and silicon deposited at room temperatures and at elevated temperatures. In addition to using two types of PLD, an investigation of the properties of tungsten oxide thin films incorporated with alkali metals was conducted. This was achieved by preparing a target using tungsten oxide with small amounts of sodium nitrate (NaNO3). The addition of alkali metals has been known to change the structure as well as the electrical, chemical, and physical properties of the bulk material. After deposition, the thin films were annealed at 450°C up to 30 hours in air. Characterization of the films' structure and morphology were made using scanning electron microscopy (SEM), x-ray diffraction (XRD), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS) both before and after annealing. Characterization of the films allowed me to determine which method of PLD as well as which substrate (glass, silicon, or sapphire) is more suitable for growing thin films suitable for photocatalysis applications.

Copyright

© Anthony Thomas Pelton

Open Access

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