Journal of Physical Chemistry & Biophysics
Open Access

Electron/hole transformation between two atomic layers

4^th International Conference on Physical and Theoretical Chemistry

September 18-19, 2017 Dublin, Ireland

Junrong Zheng

Peking University, China

Keynote: J Phys Chem Biophys

Abstract :

Electron/hole transformations on interfaces determine fundamental properties of opto-electro-chemical devices, but remain a grand challenge to experimentally investigate and theoretically describe. Herein, combining ultrafast VIS/NIR/MIR frequency-mixed micro spectroscopy and state-of-the-art two-dimensional atomic device fabrications, we are able to directly monitor the phase transitions of charged quasi particles in real time on the ultimate interfaces ��? between two atomic layers. On type II semiconductor/semiconductor interfaces between two transition metal dichalcogenide (TMDC) monolayers, interfacial charge transfers occur within 50 fs and interlayer hot excitons (unbound interlayer e/h pairs) are the necessary intermediate of the process for both energy and momentum conservations. On semiconductor/conductor (graphene) interfaces, interlayer charge transfers result in an unexpected transformation of conducting free carriers into insulating interlayer excitons between the conducting graphene and the semiconducting TMDC. The formation of interlayer excitons significantly improves the charge separation efficiency between the two atomic layers for more than 20 times.

Biography :

Junrong Zheng completed his PhD and Post-doctoral studies at Stanford University. He is Professor of Chemistry at Peking University, and a Co-founder of Uptek Solutions, a Long-Island-based laser company. He is a recipient of numerous prestigious awards including the Sloan Fellowship and the Packard Fellowship.