Prof. Paulo Cesar de Morais

Catholic University of Brasilia
Brazil

Abstract Title: Prospective Investigation of Metal-Oxide Nanofilms for High Performance Devices

Biography:

Professor Paulo César De Morais (H60), PhD, was full Professor of Physics at the University of Brasilia (UnB) – Brazil up to 2013. Appointed as UnB’s (Brazil) Emeritus Professor (2014); Visiting Professor at the Huazhong University of Science and Technology (HUST) – China (2012-2015); Distinguished Professor at the Anhui University (AHU) – China (2016-2019); Full Professor at the Catholic University of Brasília (CUB) – Brazil (2018); CNPq-1A Research Fellow since 2010; 2007 Master Research Prize from UnB. 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 (UFMG) – Brazil. With more than 13,000 citations, He has published more than 500 papers (Web of Science), delivered more than 200 international invited talks, and filed more than 15 patents.

Research Interest:

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.