posted 2 Apr 2014, 02:55 by Mette Lund Meisner
Mauricio Terrones, Department of Physics, Department of Chemistry, Department of Materials Science and Engineering and Center for 2-Dimensional & Layered Materials. The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
This talk will discuss the synthesis of large-area, high-quality monolayers of nitrogen- and boron-doped graphene sheets on Cu foils using ambient-pressure chemical vapor deposition (AP-CVD). Scanning tunneling microscopy (STM) and spectroscopy (STS) reveal that the defects in the doped graphene samples arrange in different geometrical configurations exhibiting different electronic and magnetic properties. Interestingly, these doped layers could be used as efficient molecular sensors and electronic devices. In addition, the synthesis other 2-Dimensional materials will be described. In particular, we will discuss the synthesis of WS2 and MoS2 triangular monolayers, as well as large area films using a high temperature sulfurization of WOx clusters deposited on insulating substrates. We will show that depending on the substrate and the sizes of the oxide clusters, various morphologies of layered dichalcogenides could be obtained. In addition, photocurrent measurements on these materials will be presented. The excellent response observed to detect different photon wavelengths in MoS2, WS2 and WSe2 materials, suggest these materials could be used in the fabrication of novel ultrafast photo sensors. Finally, we will show, using first principles calculations, that by alternating individual layers of different metal chalcogenides (e.g. MoS2, WS2, WSe2 and MoSe2) with particular stackings, it is possible to generate direct band gap bi-layers ranging from 0.79 eV to 1.157 eV. We foresee that the alternation of different chalcogenide layers would result in the fabrication of materials with unprecedented optical and physico-chemical properties.
Mauricio Terrones obtained his B.Sc. degree in Engineering Physics with first class honors at Universidad Iberoamericana, and was distinguished as the Best Student of Mexico in Engineering Physics in 1992. In 1994 he started his doctorate degree with Sir Prof. Harold W. Kroto (Nobel Laureate, FRS) and received his D.Phil. degree from University of Sussex in 1997. He has co-authored more than 320 publications in international journals, and counts with more than 17,000 citations to his work (His H index is 69). He has numerous awards including: the Alexander von Humboldt Fellowship, the Mexican National Prize for Chemistry, the Javed Husain Prize and the Albert Einstein medal from UNESCO, the TWAS Prize in Engineering Physics, the Carbon Prize given by the Japanese Carbon Society, the Somiya Award by the International Union of Materials Research Societies, fellowship of the American Association for the Advancement of Science (AAAS), among others. He is currently Professor of Physics, Chemistry, and Materials Science & Engineering at Penn State University. He is also distinguished Professor at Shinshu University (Japan) and director of the Center for 2-Dimensional and Layered Materials at Penn State.