MSE Seminar: Fundamental Experimental Studies on the Oxidation of Monolayer WS2
Friday, March 15, 2019
2110 Chem/Nuc Bldg, UMD College Park
Speaker: Jimmy Kotsakidis, Ph.D. Student at Monash University(Physics Dept), Australia
Title: Fundamental Experimental Studies on the Oxidation of Monolayer WS2 and Intercalation of Graphene on Silicon Carbide with the Alkali Earths
This talk will cover experiments on the 2D materials WS2 and graphene. We have examined the ambient oxidation of monolayer WS2, finding that oxidation proceeds via a photoexcitation induced (photo-oxidation) pathway requiring absorbed light at or above the trion energy. Significant oxidation occurs for WS2 exposed to laboratory lights for weeks, or a single typical photoluminescence map though is prevented for WS2 stored in darkness. I will also present findings from STM and Synchrotron XPS studies on the intercalation of mono and bilayer graphene on SiC with magnesium and calcium.
Jimmy C. Kotsakidis graduated from Monash University with a Bachelor’s of Science (Physics) and Bachelor of Electrical and Computer Systems Engineering (hons). He started his PhD in Physics at Monash University in 2016 in the field of condensed matter physics, working under Prof. Michael Fuhrer (Monash Uni) and Dr. D. Kurt Gaskill (U.S. Naval Research Laboratory) with expected completion in 2019. He is investigating the effects of doping and intercalation of graphene on silicon carbide with the alkali earth’s calcium and magnesium, as well as the fundamental properties of transition metal dichalcogenides. His research interests include the physical properties of 2D materials and associated techniques such as nanofabrication, photoluminescence spectroscopy, scanning tunneling microscopy and x-ray photoelectron spectroscopy.