Abhijit Ghosh

Date of Graduation

Summer 2009

Degree

Master of Science in Materials Science

Department

Physics, Astronomy, and Materials Science

Committee Chair

Kartik Ghosh

Abstract

Oxide based dilute magnetic semiconductors (DMS) are key materials for development of next generation multifunctional spintronics devices such as spin transistors and magnetic random access memories. However, the success of the spintronics devices critically depends on electrical and magneto-transport properties of DMS. This thesis investigates the effect of growth temperature and oxygen pressure on structural, optical, and magneto-transport properties of cobalt-doped indium oxide (In2O3:Co) DMS thin films. Thin films were grown under different partial oxygen pressures and substrate temperatures on quartz and sapphire substrates using pulsed laser deposition (PLD) technique. Structural, electrical, optical, and magneto-transport properties have been measured using various characterization techniques such as x-ray diffractometer (XRD), UV-visible spectroscopy, temperature dependent magneto-transport set-up, and superconducting quantum design magnetometer. The crystallinity of the films increases with increasing growth temperature as well as oxygen pressure during the growth as revealed by XRD. Hall effect and temperature dependence resistivity measurements reveal that the electrical transport properties (carrier density, mobility, and resistivity) in these films can be tuned by changing the growth temperature as well as oxygen pressure. Bandgap, measured using optical measurement, decreases with decrease in carrier concentration obtained from electrical measurement. Magneto-transport properties such as temperature dependent resistivity and magneto-resistance were found to be very sensitive to the micro-structural properties such as crystallinity as well as oxygen defect. These results provide basic information regarding electronic and magnetic properties of indium oxide as a prospective DMS for future spintronics applications.

Keywords

InΓééOΓéâ, electrical properties, spintronics, semiconductors, wide bandgap

Subject Categories

Materials Science and Engineering

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© Abhijit 0 Ghosh

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