Abstract:
The presentation will be focused on exploring the use of the thermal evaporation technique for fabrication of copper and copper oxide nanofilms, the latter addressed to be used as sensors of small organic molecules. The nanofilm’s thickness control is achieved through modulation of the Z-position (metal source-to-substrate distance) within the chamber. It is found that the grain size ( ? ) is strongly correlated with the film thickness (ω), being described by a power law ( ? ∝ ?%), where n is around 0.5 for the as-fabricated copper nanofilms. Measurements reveal resistivity ranging in the range of 3 to 5 µΩ´cm for the copper nanofilms, aligning closely with expectations for copper nanofilms composed of crystallites sized between 20 and 30 nm, which is consistent with the grain sizes obtained from x-ray diffraction (XRD) data. In order to produce copper oxide nanofilms, thermal annealing process was carried out at 200°C in air for 20 hours. XRD data analysis indicates mean crystallite sizes varying from about 9 nm up to about 24 nm as the nanofilm’s thickness increases. Electrical measurements indicate a p-type copper oxide semiconductor, with carrier concentrations of around 1014 cm-3 , which shows a slight decrease as the nanofilm’s thickness increases.
Biography:
Paulo C. DE MORAIS, PhD, was full Professor of Physics at the University of Brasilia (UnB) – Brazil up to 2013, Appointed as UnB’s Emeritus Professor (2014), Appointed as Guest Professor of Huazhong University of Science and Technology – China (2011), Visiting Professor at Huazhong University of Science and Technology (HUST) – China (2012-2015), Appointed as Distinguished Professor at Anhui University (AHU) – China (2016-2019), Appointed as Full Professor at Catholic University of Brasília (UCB) – Brazil (2018), Appointed as CNPq-1A Research Fellowship since 2010, 2007 Master Research Prize from UnB, 2008-member of the European ERA NET Nanoscience Committee, Member of the IEEE-Magnetic Society Technical Committee, Senior Member of the IEEE Society, 2012 China’s 1000 Foreign Expert Recipient, and 2012 Academic Excellence Award from Brazilian Professor’s Union. He held two-years (1987-1988) post-doc position with Bell Communications Research – New Jersey, USA and received his Doctoral degree in Solid State Physics (1986) from the Federal University of Minas Gerais – Brazil. He graduated in both Chemistry (1976) and Physics (1977) at UnB. Professor Morais is member of the Brazilian Physical Society and the Institute of Electrical and Electronics Engineers – IEEE. He has served as referee for more than 50 technical journals, takes part of the Editorial Board of more than 15 technical journals and has conducted research on nanomaterials for over 40 years. He has delivered more than 150 Invited Talks all over the World. He is known for his research in preparation, characterization and applications of nanosized materials (magnetic fluid, magnetoliposome, magnetic nanoemulsion, magnetic nanocapsule, magnetic nanofilm, magnetic nanocomposite, nanosized semiconductors, polymeric dots, carbon dots, and graphene quantum dots). With nearly 500 published papers in peer reviewed journals, over 12,000 citations and 15 patents, he has appeared in recent World ranking of top 1% scientists, such as 2020-Stanford, 2022-Research.com, and 2023-AD Scientific Index.
