Thesis Title

Electrical Transport Properties of Gold-Strontium Titanate Nanocomposite Thin Films

Date of Graduation

Fall 2008

Degree

Master of Science in Materials Science

Department

Physics, Astronomy and Materials Science

Committee Chair

Pawan Kahol

Keywords

nanocomposites, strontium titanate, pulse laser deposition, metal-insulator transition, temperature dependent resistivity

Subject Categories

Materials Science and Engineering

Abstract

Nano-composite thin films formed by embedding metal or semiconductor nano-particles in a host material generally exhibit interesting electrical transport properties. Temperature dependence of resistivity is one such property which finds applications in devices and sensors. The present thesis is concerned with the study of electrical, structural, and optical properties of nano-composite thin films of gold-strontium titanate on quartz substrate, which were prepared using a pulsed laser deposition technique. Thin films having different compositions of gold in strontium titanate were grown at room temperature. The structural characterizations of the films using x-ray diffraction reveal that the films with lower concentrations of gold are amorphous. Optical characterization using uv-visible spectroscopy shows increased light absorption with increased gold concentration. For electrical characterization, we studied the current-voltage characteristics and the temperature-dependent resistivity measurements down to 50K. Current-voltage curves show linear behavior indicating the Ohmic nature of the materials, and temperature-dependent resistivity results provide clear signature of a metal-toinsulator type transition as the concentration of gold is decreased.

Copyright

© Satya Rama Naga Lakshmi Ganti

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