Enabling integration of 2D and 3D materials
Name of applicant
Joachim Dahl Thomsen
Amount
DKK 350,000
Year
2018
Type of grant
Internationalisation Fellowships
What?
2DMs are atomically thin crystals with a wide range of electronic properties, e.g. graphene (a metal), hexagonal BN (an insulator), MoS2 (a semiconductor), and Bi2Se3 (a topological insulator). Through a research project at the Massachusetts Institute of Technology (MIT) I will investigate the fundamental design rules underlying the control of interfaces between two-dimensional materials (2DMs) and "standard" three-dimensional metals such as Au, Ag, Nb and Ta. I will find conditions that lead to epitaxial deposition of these metals on different 2DMs such as graphene, hBN, MoS2, and Bi2Se3, and examine the role of surface chemistry on island nucleation, epitaxy, and growth.
Why?
In order to contact 2DMs electronically and harness the full potential of their physical properties we need to connect them with standard three-dimensional materials (3DMs). The creation of well-defined interfaces with single domain epitaxy and low interface defect density between 2D and 3DMs is a key challenge for employing 2DMs in applications such as electronics, opto-electronics, and catalysis. Forming high quality interfaces reliably can lead to improved device performance in e.g. flexible photodetectors and electronic components. Despite their importance, the formation and the control of the interfaces between such dissimilar materials remains relatively unexplored and constitutes a significant challenge because of the dissimilar chemical bonding and structure across such interfaces.
How?
MIT hosts the only transmission electron microscope (TEM) worldwide that is capable of depositing the various metals under well-controlled ultra-high vacuum conditions required for optimal epitaxy. There I will investigate the relative importance of process parameters (such as temperature and deposition rate) which leads to the epitaxial deposition of metal islands, and investigate the nanoscale nature of the interface with the TEM.