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Electronic and Transport Properties of Carbon Nanostructures Eduardo Costa Girão Propriedades eletrônicas e de transporte de nanoestruturas de carbono – Electronic and transport properties of carbon nanostructures Fortaleza - CE Dezembro / 2011 Eduardo Costa Girão Propriedades eletrônicas e de transporte de nanoestruturas de carbono / Electronic and transport properties of carbon nanostructures Tese apresentada ao Curso de Pós-Graduação em Física da Universidade Federal do Ceará como parte dos requisitos para a obtenção do título de Doutor em Física. Prof. Antônio Gomes Souza Filho / Prof. Vincent Meunier DOUTORADO EM FÍSICA DEPARTAMENTO DE FÍSICA CENTRO DE CIÊNCIAS UNIVERSIDADE FEDERAL DO CEARÁ Fortaleza - CE Dezembro / 2011 Tese de Doutorado sob o título Propriedades eletrônicas e de transporte de nanoestru- turas de carbono / Electronic and transport properties of carbon nanostructures, defendida por Eduardo Costa Girão e aprovada no dia 20 de Dezembro de 2011 em Fortaleza, Ceará, pela banca examinadora: Prof. Antônio Gomes Souza Filho Departamento de Física - Universidade Federal do Ceará Advisor Prof. Vincent Meunier Department of Physics, Applied Physics, and Astronomy - Rensselaer Polytechnic Institute Advisor Prof. Antônio José Roque da Silva Laboratório Nacional de Luz Síncrotron and Instituto de Física - Universidade de São Paulo Prof. Douglas Soares Galvão Instituto de Física ‘Gleb Wataghin’ - Universidade Estadual de Campinas Prof. François M. Peeters Department of Physics - University of Antwerp Prof. Humberto Terrones Department of Physics - The Pennsylvania State University and Departamento de Física - Universidade Federal do Ceará To my parents, Emília and Airton and to my wife Adriana Acknowledgements Well, I have to thank a lot of people. First of all, I thank God for everything. Each person knows his/her life experiences better than anyone else and, in my case, I know the importance He has in my life. I thank Him for showing me where to go and for giving me all the tools I needed to construct everything I have. I thank my wife, Adriana, for being by my side for the last 11 years. I can not imagine my life without her. I thank her for the good moments, because they made us happy, and also for the bad ones, because they made us stronger. Along these years together, we made right and wrong choices, but the best choice I made was you. Thank you for letting me be your choice. I thank my family for being my first support, my first school. Despite my defects, I am very happy with who I am and a great part of it was constructed with what I learned from my parents. Thanks for being strong when distant, thanks for being lovely when close. I thank Professor Antônio Gomes Souza Filho for being my advisor since I was an under- graduate student. It has been hard to work with completely different tools, but you have always tried to direct me to the right path. I thank you for being sincere in all the stages of my academic trajectory. In special, I thank you for not letting me to take the wrong choice. Your calm was fundamental to show me the best decision to make and it has conducted me to a position from where I can see good things ahead. I thank Professor Josué Mendes Filho for the motivation. I had some tough moments during my the academic path, but the few words I heard from him during these times were enough to make me confident that I could get over the problems and make a good job at the end. I thank Professor Solange Binotto Fagan for introducing me to the field of theoretical cal- culations. Today I’m very happy with the area I chose to work and you have great influence on this decision. Thanks for your advising when I was a undergraduate, during the master’s and in part of my PhD. When I went to Oak Ridge, I had help from people that behaved like old friends of mine, but without even knowing me. Their attitudes made a huge difference for me. So thank you guys, Lalo, Alejandro and Daniela! You were (and are) real friends. Just know that, wherever I’ll be, you’ll have a friend there. I also thanks the other guys from Oak Ridge, Viviane, Álvaro, Miguel, Paschoale, Bobby, and Deb Holder. Staying far from home in a place you do not know is usually hard, specially in the beginning, but you guys made it all easier for me and make me fell a little more like home. I also thank Professor Humberto Terrones who I meet in Oak Ridge. It has been very good changing ideas with you. I hope we have more opportunities for coffee time. I thank you for you support in Oak Ridge and here in Fortaleza. I have had a great time in Troy. Work made me happy there, but I also made good friends. My days always got better after a ride in the “Red Hawk Shuttle”. Karen, James, Sean and all the other drivers made my everyday easier after the ride and nicer after the chat. I want you to know that your work and friendship were very important to me. Thanks a lot. While being in US, I could still fell a little like in Brazil. This is because Adriana and I had our friends “Don” Fernando and Sônia and their kids Mariel, Nicolas and Gabriela. We have had very good moments in Troy and I really want this friendship to last forever. Fernando, I will never forget that crazy journey to New York city, that was a lot of fun. Thank you guys for the help and friendship. Leo is another good friend I made in Troy. Together with Adriana, we had a lot of fun hanging out. It was very nice working with you everyday and I wish you all the best in your PhD. Thanks for the friendship. Even though I have already cited Dr. Eduardo Cruz-Silva, I need to dedicate some more lines to him. Lalo helped me like a brother. His help with the arrangements for my arrival in Oak Ridge were enough to make me grateful. But once I got to Oak Ridge, I had the opportunity to know him better. More than I expect, Lalo revealed to be a great friend. But there is more. Lalo is great researcher and I am also happy for having the chance of changing ideas and making science with him. Lalo and his lovely wife Marcia are friends that will always be in my heart. Thanks you guys for everything. I also thank my friends from the Physics Department in UFC. Well, I know these guys for almost 10 years and I thank God for giving me such good friends. Time goes by and we are naturally getting far from each other, but the friendship is the same and I thank you guys for all the support and the good moments. I really wish all the best for you. In special, I thank my closer friends Acrísio, Aldi and Abraão. Acrísio and I worked to- gether for years. Facing the challenges of science with a good friend was very good and I thank him for all his support. The same applies to Aldi, such a source of joy during days of hard work. Abraão stayed away from physics for some time, but even in that time, he was a close friend and his support was very important to me. We are now geographically far from each other, but there is no distance for friendship. I wish success for your guys in the new challenges you are about to face. I have another special thank to my friends Antônio Márcio and Lavor for their attention when hosting me and Adriana in Recife. I also thank all my other friends not related to the University. Each of you guys have, somehow, a special contribution for my achievements. I thank Oak Ridge National Laboratory for all the support during my stay in Tennessee. I thank Rensselaer Polytechnic Institute all the support and for providing me the best work environment I have ever had to develop my work. I thank Universidade Federal do Ceará for all the support during my whole academic life. I thank Brazilian agency CNPq for the precious financial support which made it possible for me to develop my academic work when I was as undergraduate student, as well as during my master’s and PhD. I thank Brazilian agency CAPES for the financial support during my stay in USA through the sandwich program fellowship. I thank my colleagues from Universidade Federal do Piauí, specially Professors Bartolomeu Cruz Viana Neto and Cleânio da Luz Lima, for all the support during my initiation in the institution. Finally, I have a special thanks to Professor Vincent Meunier. If I am happy with the final result of my PhD and if I am optimistic about the future of my professional life, Vincent is especially responsible for that. Working with him made a huge difference in my life. It gave me back the pleasure of working with science. Thanks for trusting me and for giving me good projects to work on, thanks for the motivation, thanks for showing me what I could do. Some people are lucky for having a good boss as a scientist, some are lucky for having a good boss as a person, I was lucky for having both. Thanks, Vincent, for being the best boss I could ever have. “I’m a great believer in luck, and I find the harder I work the more I have of it.” Thomas Jefferson Resumo À medida que o limite de miniaturização da eletrônica baseada no silício aproxima-se do seu limite, alternativas em estado sólido devem ser investigadas na busca da diminuição da escala de tamanho de dispositivos operacionais, ao mesmo tempo em que se deve considerar problemas de crescente interessse como dissipação de calor e ruído associado com a baixa di- mensionalidade.
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