Top-down production of artificial low dimensional materials for study of static and dynamical properties

Abstract:  Two dimensional (2D) semiconductors and their artificial structures hold great promises for electronic, optoelectronic, and quantum devices. The best quality monolayers for exploring the exotic quantum properties so far are mostly produced by scotch tape exfoliation, which is stochastic and often yields microscopic sized monolayers. I am going to talk about a few new scalable and controllable processes to: a) disassemble van der Waals (vdW) single crystals layer-by-layer into monolayers with near-unity yield, high quality, and macroscopic dimensions and b) produce additional low dimensional structures such as monolayer nanostrips with designed edge and width conformation. High-quality and large-area crystals will allow us to further assemble them into artificial heterostructures and integrate into multiple probe techniques such as optical spectroscopy, electron diffraction as well as time and angle resolved photoemission spectroscopy to explore the key static and dynamic properties in these low dimensional systems. I will talk briefly about a few examples including the light induced electron and lattice dynamics and nonlinear optical responses. Obtaining high quality materials with enhanced yield will take us one step closer to mass production and commercialization of the 2D devices in the future. 

Bio: Fang Liu is an assistant professor of chemistry at Stanford University, started 2020. Her research aims to develop scalable and controllable processes to synthesize/fabricate low dimensional materials and their artificial structures and unravel their novel static and dynamical properties. Prior to her current position, she was a DOE Office of Energy Efficiency and Renewable Energy (EERE) postdoctoral fellow in the group of Prof. Xiaoyang Zhu at Columbia University. Her postdoctoral research focused on using femtosecond extreme UV in probing time and angle resolved photoemission spectroscopy of 2D materials. Prior to working in Columbia, she worked under the direction of Prof. Marsha I Lester at the University of Pennsylvania. She received her Ph.D. in 2015 and worked as a postdoc in the same group in 2016. At UPenn, she used time resolved spectroscopic techniques to study spectroscopy and photochemistry of Criegee intermediates. She received her B.S. in chemistry at Peking University. 

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