School of Materials Science and Engineering A thesis submitted to the Nanyang Technological University in fulfillment of the requirement for the degree of Doctor of Philosophy 2006 ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library I would like to take this opportunity to express my heartfelt gratitude and appreciation to my thesis supervisor, Professor Chee Cheong Wong whose guidance and support has always been a source of motivation to me throughout this work. While working with him, I learned the level of independency that a motivated researcher has to pursue in his research career to explore novel ideas, concepts and to trust my innate abilities and intuition. He rendered me an encouraging, goal-oriented and prolific atmosphere in order to practice a self-motivated research by making individualistic decisions as well as made sure that my research works remain on the right track without which I would not have come up to this stage.