Date of Graduation

Fall 2009

Degree

Master of Science in Materials Science

Department

Physics, Astronomy, and Materials Science

Committee Chair

Robert Mayanovic

Abstract

Transition metal oxides have been the subject of intense study by material scientists and chemists for many years. They represent a unique solid state material which can undergo reversible phase transitions from insulators (or semiconductors) to metals when they undergo changes in ambient conditions. It has long been established that vanadium oxides undergo these reversible phase transitions. When irradiating infrared light on thin films of VO2, a phase transition from a semiconductor to a metal causes the IR light to go from transmitting to reflecting. This study investigates phase transitions of metal oxide thin films in which visible light can be changed from transmitting to reflecting. Such a device would broaden the field of optoelectronics, optical neural networks, and advanced detector systems. An optoelectronic device from a thin film heterostructure of vanadium and titanium oxides is fabricated in this study. When a voltage was applied to the device, HeNe light responded to a reversible phase transition from a semiconductor to a more metallic material. Light on the transmission side experienced a significant drop while simultaneously experiencing a corresponding increase in reflectivity.

Keywords

vanadium pentoxide, titanium dioxide, transition metal oxides, optoelectronic, heterostructure, phase transition, optical neural network, photoexcitation

Subject Categories

Materials Science and Engineering

Copyright

© David Michael Lamb

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