Thesis Title

The Electrical Properties And Microstructure Of An Ion Beam Mixed Metal-Polymer System

Author

Runhui Huang

Date of Graduation

Summer 1999

Degree

Master of Science in Materials Science

Department

Physics, Astronomy and Materials Science

Committee Chair

Ryan Giedd

Subject Categories

Materials Science and Engineering

Abstract

Ion beam mixing of the surface of polymers with metal films is done by ion implanting through a thin metal film. The metal layers are evaporated on the polymer substrate surface before ion implementation. A 50keV, nitrogen ion beam with a dose in the range of 10¹⁶ ions/cm² and a dose rate current of 100 and 200 uAmp mixes the metal and polymer at the interface. The polytetrafluorethylene samples (PTFE) mixed with Cr metal layers. The optical properties indicate surface and near-surface structure. SEM pictures show a smooth surface after implantation and cracks in the metal layer. The thermal damage results in gas evolution during implantation. The resistivity is reduced over the resistivity of ion implanted polymers no metal layer. The DC conductivity increases with increasing temperature. The temperature coefficient of resistance decreases with increasing metal layer thickness. Coulomb gap and thermal Hopping theories are used to fit the experiment data. The results show the thin Cr layer samples more like Coulomb gap conducting materials; the thick Cr layer samples more in the Hopping conducting regions. A possible model of ion implanted metal/polymer system is shown at the end of this thesis. The varying metal layer thickness results in the different microstructures. The mixing condition and metal layer thickness directly affects the conducting mechanism.

Copyright

© Runhui Huang

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Dissertation/Thesis

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