Topic: Glass Materials for Next-generation Computer Memory
Speaker: Associate Prof. Gang Chen, Ohio University
Time: 10:00, June 9, 2017
Venue: Room 602, Building of State Key Laboratory of Luminescent Materials and Devices, Wushan Campus
Abstract:Chalcogenide glasses have been used in computer random access memory (RAM) technology and show threshold switching in optical/electrical properties under external disturbance. An example is the Conductive-bridging Random Access Memory (CBRAM), a type of Resistive Random Access Memory (RRAM) that shows threshold switching in resistance under electrical excitation. The CBRAM has advantages of high switching speed, low power consumption, excellent scalability and high endurance over the flash memory and is becoming a major player in the field of non-volatile memory. While a great deal of effort has been dedicated to commercializing the CBRAM technology, the atomistic mechanisms behind the fast switching of the amorphous chalcogenides remain elusive. The unsolved key question is related to the origin of the conductive filaments that are responsible for the switching.  To tackle this problem, we synthesized Ag-doped Ge-Se thin films and CBRAM devices and study the kinetics of switching of the CBRAM devices using cyclic voltammetry. It was found that the early stage of switching was not related to formation of metallic filament. We prose a new atomistic model for the mechanism of switching.
Biography:Dr. Gang Chen is an Associate Professor in the Department of Physics and Astronomy at Ohio University. He received his B.S. in Physics from the University of Science and Technology of China in 1999, M. S. in Photonics from Lehigh University (USA) in 2002, and Ph.D. in Materials Science and Engineering from Leigh University in 2004. After spending three years at Department of Energy’s Argonne National Laboratory (USA) as a postdoctoral fellow, he joined Ohio University as a tenure-track Assistant Professor in 2007 and was promoted to Associate Professor with tenure in 2013. His current research focuses on amorphous semiconductors with applications in non-volatile computer memory such as phase-change memory materials and conductive bridging random access memory materials. His research group is specialized in amorphous materials synthesis methods such as melt-quenching, thermal evaporation, sputtering, sol-gel and electrodeposition as well as advanced X-ray characterization techniques such as small- and wide-angle X-ray scattering, X-ray absorption spectroscopy and X-ray photoelectron spectroscopy to understand the structure-property relations of amorphous materials.