Access Type
Open Access Dissertation
Date of Award
January 2010
Degree Type
Dissertation
Degree Name
Ph.D.
Department
Physics and Astronomy
First Advisor
Ratna Naik
Second Advisor
Karur Padmanabhan
Abstract
ABSTRACT
A STUDY OF STRUCTURE-PROPERTY CORRELATION IN V2O5 AND TiO2 BASED THIN FILMS AS FUNCTIONAL MATERIALS
by
CHANDRA THAPA
June 2010
Advisor: Dr. Ratna Naik
Co-Advisor: Dr. K. R. Padmanabhan
Major: Physics (Condensed Matter)
Degree: Doctor of Philosophy
The focus of this thesis is to study the structure-property correlation in thin films of V2O5 and TiO2 based transition metal oxides as functional materials. V2O5 is investigated as a cathode material for lithium ion battery and TiO2 as a high-K dielectric material.
We studied V2O5 thin films prepared by spin coating using three different types of precursors, MOD precursor, sol-gel organic precursor and sol-gel inorganic precursor. On the basis of structural and electrochemical studies, we find that the capacity is dependent on the degree of non-stoichiometry. We have also studied the effect of addition of Ti. Although Ti doping enhances non-stoichiometry, the capacity was found to increase only in 5% Ti-doped sol-gel film. This means the optimal degree of non-stoichiometry is crucial to enhance the capacity.
TiO2 is one of the possible high-k dielectric materials because of its very high dielectric constant. We studied leakage characteristics, the dielectric strength and frequency dependent behavior of dielectric constant of TiO2 thin films prepared by MOD, sputter deposition and annealed at different temperatures. We find dielectric constant increasing with the increase in annealing temperature and leakage current density improvement by almost one order of magnitude with each 1000C increase in annealing temperature. Since TiO2 possess two distinct thermodynamical phases: anatase and rutile, which dramatically influences the values of dielectric constant and leakage current density, it is crucial if we can stabilize the phase of TiO2 by doping. We find that 20% Zr-doping completely stabilizes TiO2 phase in its anatase form. The dielectric constant of the films is independent of annealing temperature but the leakage current density improves by one order of magnitude with every 1000C increase in annealing temperature.
Recommended Citation
Thapa, Chandra, "A Study Of Structure-Property Correlation In V2o5 And Tio2 Based Thin Films As Functional Materials" (2010). Wayne State University Dissertations. 32.
https://digitalcommons.wayne.edu/oa_dissertations/32