The Effect of Nonmagnetic Doping and Growth Temperature on the Magneto-Transport Properties of Manganese and Cobalt Doped Zinc Oxide Dilute Magnetic Semiconductors

Date of Graduation

Summer 2006

Degree

Master of Science in Materials Science

Department

Physics, Astronomy, and Materials Science

Committee Chair

Kartik Ghosh

Abstract

Dilute Magnetic Semiconductors (DMA) are a rare group of promising materials that utilize both electronic charge, a characteristic of semiconductor materials, and electronic spin, a characteristic of magnetic materials. This combination of charge and spin degrees of freedom in a single material leads to a unique interplay of magnetic, optical, and electronic functionalities. Recently, DMS have received much attention due to their potential use in novel spintronic devices and quantum bits. Oxide based DMS show promise of ferromagnetism at room temperature. Zinc Oxide (ZNO), a short wavelength transparent opto-electronic material, is an interesting prospect for spintronics due to its unique magnetic, electrical, and optical properties. ZnO doped with a transition metal like Mn, Co, or Fe and a nonmagnetic metal like Al, V, or Cu is a DMS that has strong exchange interaction between localized d electrons and SP band carriers. In this work, high quality thin films were deposited on c plane of sapphire single crystals using pulsed laser deposition (PLD) technique. The effect of nonmagnetic doping using metals such as Al and Cu and growth temperature of Zn1-xMnxO (x=0.15) and Zn1-xCoxO (x=0.05) thin films were studied using X-Ray diffraction (XRD), Raman spectroscopy, Atomic Force Microscopy (AFM), scanning Electron Microscopy (SEM), and Magneto-Transport techniques. XRD and Raman spectra confirm the epitaxial growth with a strong orientation along the c-axis, while AFM and SEM reveal surface micro structural information about the DMS films. Magneto-Transport studies quantify the carrier concentrations and motilities of various DMS films grown using PLD. Finally, the results are compared with theoretical values.

Keywords

semiconductor, ferromagnetism, pulse laser deposition, zinc oxide, spintronics

Subject Categories

Materials Science and Engineering

Copyright

© Govind Mundada

Citation-only

Dissertation/Thesis

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