For more than a decade after the discovery of the unique physical properties of graphene, two-dimensional (2D) materials have been attracting the attention of the nanoscale research community and beyond. 2D materials can be stacked on top of the other, or be interfaced with organic molecules, and this leads to a paradigm shift in the way heterostructures can be artificially built.
In this talk, Professor Wee will introduce his group’s recent work in the use high-resolution scanning tunneling microscopy/spectroscopy (STM/STS) to study the atomic structure and local electronic properties of 2D MoS2 and WSe2 monolayers on HOPG substrates, and show that the electronic bandgaps can be tuned by strain at grain boundaries and dislocations.
Using PTCDA as a prototype semiconductor organic molecule, he will show that a monolayer TMD can effectively screen an organic-inorganic heterointerface. He will also discuss the fabrication and electronic properties of a lateral doped/intrinsic heterojunction in 2D WSe2, partially covered with a molecular acceptor C60F48. In that last part of his talk, recent results of DAP on VSe2 will also be introduced.
ABOUT THE SPEAKER
Professor Andrew Wee is a Professor of Physics and Vice President (University and Global Relations) at the National University of Singapore (NUS). He is also the President of the Singapore National Academy of Science. His research interests include scanning tunneling microscopy (STM) and synchrotron radiation studies of the molecule-substrate interface, graphene and 2D materials, and related device studies. He is an Associate Editor of ACS Nano, and on the Editorial Boards of several other journals. He holds a BA (Hons) and MA from the University of Cambridge, and received his DPhil from the University of Oxford. As a world-leading surface scientist, Professor Wee has authored more than 500 publications with an h-index of 73.