The BNC Faculty Seminar Series is designed to provide faculty a platform to present an overview of their research and the opportunity for collaborative discussion with other BNC faculty and researchers across six colleges and 15 academic units.

Dmitry Zemlyanov, Senior Research Scientist - Surface Science Application, Birck Nanotechnology Center

Join Zoom: https://purdue-edu.zoom.us/j/91754078808

Title: Growth and in-situ characterization of 2D materials

Abstract: 2D materials and nano-materials often exhibit unique electronic, mechanical and thermal properties, which cannot be found in their bulk forms. Surface nature makes these materials prone to contaminations. Therefore, in-situ growth and characterization of 2D materials is crucial step for fundamental property understanding, smart material design, functionalization, fabrication, etc. The Surface Analysis Facility at Birck Nanotechnology Center, Purdue University, is equipped with state-of-art characterization tools such as X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy/spectroscopy (STM), high–resolution electron energy loss spectroscopy (HREELS), low energy electron diffraction (LEED). These techniques are combined with synthesis capabilities (PVD, CMD and vacuum ALD) creating exceptional opportunities for researchers in the area of 2D and nano-materials.

In this talk, I would like to demonstrated a few examples of synthesis and in-situ characterization of 2D materials. For instance, Pd and Pt tellurides and selenides are Dirac semimetals demonstrating fascinating quantum phenomena such as superconductivity, magnetism, topological order and excitation of surface plasmons. Due to the strong interlayer coupling and electron level hybridization, it is extremely challenging to prepare large-area monolayer of PdTe2 and PtTe2. We developed a simple method of epitaxial growth of PdTe2 and PtTe2 by direct tellurization of platinum and palladium surfaces, which allowed us to synthesize large-area and high-quality monolayer films of these two materials. As another examples, I would like to demonstrated nanomanipulation of MoTe2 and MoS2 and interaction of metal with oxide support. The strong metal support interaction (SMSI) is among the best-known classes of oxide-metal interfacial interactions in heterogeneous catalysis, but there is limited insight in the atomic-scale understanding of the structure and phase of the SMSI oxide. We have investigated interfacial interaction between ZnOx oxide and Pd metal under varying gas phase conditions. Structural transformations from bilayer to monolayer and then PdZn alloy confirmed that zinc oxide as a non-reducible oxide, can spread on metal surface and show an SMSI-like behavior in the presence of hydrogen.

Bio: Dmitry Zemlyanov received his Ph.D. in Physics and Mathematics from the Novosibirsk State University, Russia, in 1995. He is currently a Senior Research Scientist - Surface Science Application at Birck Nanotechnology Center, Purdue University. He held research and teaching positions in premier scientific organizations in Russia, Ireland and Germany prior to joining Purdue and published over 165 journal papers in the areas of surface science, catalysis and materials science. At Purdue, he collaborates with a wide variety of research groups from College of Science and College of Engineering enabling them to develop and apply advanced scientific instrumentation in the area of surface characterization.